What to do in Punggol when two bags of rice, bottles of oil or packs of tissues have different sizes and attractive prices? Compare the price per equal unit, not just the number printed in the biggest font. Singapore’s Competition and Consumer Commission and Consumers Association expanded their supermarket unit-pricing pilot in October 2026, making it easier to compare selected products using measures such as dollars per kilogram, per litre, per 100 grams, or per item.

Did you know that Don Don Donki at Waterway Point is one of the locations listed in the official 2026 expanded pilot? The government identifies its Punggol outlet among participating Don Don Donki stores, while the wider pilot includes major supermarket chains and selected online shops. That does not mean every product has a unit-price label or that one chain is consistently cheapest. The pilot’s categories and implementation vary, and an equal-unit calculation is only one part of deciding what a household should buy.

This practical family shopping activity teaches fair comparison, basic Mathematics and responsible budgeting. It is not a live Punggol price survey and does not claim any particular shelf price or promotion is still running. Check the current label and final checkout conditions. The most economical choice is often the right quantity at a reasonable unit cost—not an enormous discounted pack that the household cannot use safely.

The six-step equal-price shopping challenge

• Pick two or three genuinely comparable items with different pack sizes.
• Read the actual selling price, quantity and unit of measurement.
• Find an official unit-price label where available or calculate your own.
• Convert only like units: grams to kilograms or millilitres to litres.
• Check promotions, bundle conditions, product quality, expiry and usable quantity.
• Buy the amount the family needs, then discuss why the lowest unit price did or did not win.

A unit price is a common measuring ruler

Imagine two different pack sizes that both contain the same general product. One might look cheaper because the total price is smaller, while the other might cost less for each 100 grams. Unit pricing turns them into comparable measurements. It answers the narrow question: how much money is paid per equal measure of product?

The Competition and Consumer Commission’s official unit-pricing guide defines unit price using weight, volume and quantity and explains the ongoing pilot. This is a useful consumer skill, but it is not proof that the lowest unit-price product meets every household need.

Why Punggol households can explore this now

Stage 2 of the Singapore supermarket unit-pricing pilot began on 1 October 2026 and expanded participating operators and grocery categories. It provides a real current example of how public consumer information can make everyday price comparisons more transparent. Families can practise in a participating local store or with legitimate online listings.

Participation and labels vary by outlet and product. Do not make a scavenger hunt depend on finding one specific item’s label. If the selected product has no unit-price display, the child can use its selling price and net quantity to calculate a comparable number instead.

The official Punggol pilot connection

The CCS September 2026 unit-pricing page lists Don Don Donki Waterway Point at 83 Punggol Central, #B1-10B among its participating Don Don Donki locations. This is a grounded Punggol example, not a claim that all goods at that outlet display unit prices.

Check the present outlet, operating conditions and shelf labels before travelling. The family does not need to go there specifically; other participating supermarket chains and online shops may support the same activity. A familiar Punggol shop simply makes the principle concrete.

Which operators are included in Stage 2?

CCS says the expanded pilot includes NTUC FairPrice, Sheng Siong, Prime Supermarket, Cold Storage, Giant, Don Don Donki and RedMart. Launch schedules differ: the published programme describes the expanded pilot starting on 1 October 2026 for several partners, with Cold Storage and Giant scheduled for 1 November 2026. Participating online platforms are also being added progressively.

Do not assume that an operator’s national involvement means every product in every shop is covered at the same moment. Read the actual date and terms of the pilot and the present store shelf. This article records the October 2026 public announcement rather than guaranteeing future rollout.

A pilot is not a permanent guarantee

The pilot exists to test consumer usefulness and implementation across different categories and retailers. The official page describes fixed participating periods and surveys intended to guide future decisions. It should not be described as a permanent statutory requirement that every Punggol retailer must display a uniform unit price.

Treat a missing label appropriately. You may calculate a unit price yourself for a comparison, but should not accuse a shop of breaching a rule solely because a particular product lacks a pilot display. The current regulatory and programme context matters.

Start with products that truly match

A fair comparison might use two brands of ordinary rice with equivalent intended use, or two plain cooking oils of the same relevant type. Comparing a specialised premium ingredient with a basic substitute may be mathematically possible, but the products may have different characteristics and household value.

Ask whether the family would actually use both items interchangeably. If not, a lower unit price may be irrelevant. The best first learning pair is two packages that fulfil the same practical need while having clearly stated sizes.

The selling price and unit price answer different questions

The selling price tells you what the package costs today. The unit price tells you its cost for a standard amount. A smaller package may be easier to afford or use even when its unit price is higher. A large pack may be attractive per kilogram but inappropriate for a small household.

Keep both numbers in the decision note. A family with a limited grocery budget needs to know the immediate cash required as well as the theoretical cost per unit. Economical shopping means understanding the trade-off, not blindly selecting the mathematically cheapest bulk product.

How the calculation works

Divide the displayed selling price by the amount, then multiply by the standard unit you want. If a hypothetical 500-gram pack costs S$4.50, the price per 100 grams is S$4.50 divided by five, or S$0.90. For a 1-kilogram pack costing S$8.20, the price per 100 grams is S$8.20 divided by ten, or S$0.82.

These are invented examples, not current Waterway Point prices. They show that the larger pack can have a lower unit price. Whether the family should purchase it depends on whether it will consume the quantity safely and whether the products are genuinely comparable.

Be consistent with grams and kilograms

One kilogram equals 1,000 grams. A label per kilogram should not be compared numerically with a different label per 100 grams without conversion. If an item costs S$0.80 per 100 grams, that equals S$8 per kilogram, assuming the price relationship is linear.

Ask a child to write the unit beside each value, not only the number. ‘0.80’ without ‘per 100 g’ can be misleading next to ‘8.00 per kg’. Clear units are a basic mathematical safeguard against a false bargain.

Be consistent with millilitres and litres

One litre equals 1,000 millilitres. A hypothetical 500-millilitre bottle costing S$1.50 has a price of S$3 per litre. A 750-millilitre bottle costing S$2.10 costs S$2.80 per litre. The larger bottle has the lower unit price in this illustration.

Do not treat millilitres and grams as interchangeable for different liquids or foods. A volume-to-mass conversion requires information about density, which this simple shopping activity does not supply. Compare within the same unit type or follow an appropriate official unit-price label.

What about prices per 100 sheets?

Some household products are sold by the number of sheets or pieces rather than weight. CCS explains that standard quantity units can include price per item, and the CASE consumer guide discusses price per 100 sheets for suitable paper products. This can help compare differently sized tissue packages.

Check the number of sheets and whether their dimensions, ply and quality are comparable. A package with more sheets may still contain smaller or thinner material. The unit price answers quantity-based cost, not every question about usefulness.

What about eggs?

CCS gives eggs as a category where weight-based comparison can be useful, for example per 100 grams. Egg packs can differ in number and average size. Comparing only the price for six versus ten eggs may hide differences in the total amount of food.

Use the weight-based measure if properly shown and relevant. If exact net mass is unavailable, do not invent it from visual impressions. Some households choose eggs by size, recipe requirements or preferred characteristics, and the most economical choice depends on those needs.

The product label may be missing

A participating supermarket might display unit prices for selected product groups but not the specific item you want. You can still use the package’s displayed net quantity and selling price to make a calculation when appropriate. Keep the result labelled as your own arithmetic.

Do not stop staff from working or demand that they explain the entire pilot when a label is absent. If a shelf price appears unclear or inconsistent, ask politely through the retailer’s normal customer-service process. A family activity should remain courteous.

How to compare a bundle offer

Bundles may contain multiple identical packs, such as two bottles for one combined price. First calculate the total physical quantity and actual combined cost, then find the unit price. Do not use a single-pack price with the bundle’s total amount, because that mixes two different purchase conditions.

Check whether the promotion requires a membership card, app, coupon or purchase of a different item. The cheapest calculated unit price is not available to the family if it does not meet the promotional conditions. Use the final price that it would actually pay.

What does ‘buy two, get one free’ mean mathematically?

If three identical products are supplied for the price of two, the effective unit cost is based on three products received and the actual total paid. A hypothetical S$3 item offered as three for S$6 costs S$2 per item under the offer. That calculation says nothing about whether the family needs three.

A household that consumes only one before the product expires may waste the other two. Then the attractive unit price does not translate into practical value. The real decision must include expected use and safe storage.

Compare discount labels carefully

A bright percentage-off sticker can distract from the final selling price. Check which product and size the discount covers, whether another purchase is required and whether the displayed label has already incorporated the promotion. Use the actual payment conditions for unit-price calculation.

Do not combine multiple incompatible discounts on paper as though all will apply at checkout. If the final charge differs from the expected shelf price, seek clarification and retain the receipt. A mathematical exercise should use the price the family can genuinely obtain.

GST and displayed prices

Retail shelf labels and online pricing should be read according to the applicable current display requirements. A family should compare amounts on a consistent tax basis, especially when one number comes from a shelf label and another from a marketplace listing. The final transaction can include delivery or other legitimate charges.

Do not compare a gross checkout price for one item with a tax-excluded hypothetical quotation for another. Use the actual payable cost for equivalent purchase conditions. This also prevents an apparent discount from being created by changing the tax basis.

Online unit-price displays are part of the 2026 expansion

The CCS Stage 2 announcement says online unit pricing was introduced for selected categories, including Sheng Siong and RedMart beginning in October 2026, with other providers progressing according to rollout arrangements.

Online shopping can make comparison convenient, but the family must still consider delivery fees, minimum orders, substitutions, membership conditions and stock. The lowest displayed price per 100 grams may not produce the lowest all-in household order.

Delivery fees can reverse a small saving

Suppose a hypothetical online shop offers an item at S$0.10 less per 100 grams, but the family must pay a delivery charge it would not otherwise incur. The unit-price saving may be smaller than the additional fee. This does not make unit pricing wrong; it means the purchasing decision contains more than one cost component.

Ask whether the delivery is already necessary for other groceries and whether the comparison is fair. Do not invent an all-in saving without including actual eligible charges and the order’s real quantities.

Price per unit is not nutritional quality

A packet with lower cost per 100 grams may contain more sugar, salt or ingredients unsuitable for the family. Nutrition labels and public health recommendations address different questions from price. A Punggol parent can use unit pricing to compare cost while also checking what the food contains and whether the household actually wants it.

Do not treat the lowest unit price as a health recommendation. Relevant allergies, religious dietary needs and personal preferences may rule out a product regardless of its price. Children should learn that decisions require several factors.

Compare like-for-like food quality

Product attributes such as grade, cut, freshness, preparation, packaging and origin can change the practical comparison. Two meat packs might contain different proportions of bone, marinade or usable food. A perfectly correct price-per-kilogram calculation can still compare items that serve different purposes.

Choose the level of comparison appropriate to the household’s decision. If the products differ materially, write that the unit price alone cannot settle which is better value. This is not an excuse to ignore arithmetic; it is an important limit on how the result should be interpreted.

The usable quantity is sometimes what matters

Frozen food, fruit with large inedible parts and products that require preparation can have different usable yields. The displayed unit price usually reflects the labelled quantity, not the exact amount of edible prepared food a particular family will obtain.

Do not invent a yield percentage to make one product win. If the household already knows its usual recipe and waste pattern, it can reason carefully. For a simple beginner exercise, compare products with similar usable quantities and note the limitation.

Storage and household size can beat the largest pack

A household with two people may not consume a very large package before its recommended period of use. A large bag can also require storage space that is unsuitable in a small flat or humid conditions. Paying less per kilogram is not a saving if much of the product is discarded.

Think about what the family will actually use during the relevant period. A smaller package may cost more per unit but still result in less spending and waste overall. This links naturally to our Punggol seven-day food-waste challenge.

Expiry and food safety come before bulk buying

Read the product’s actual date label and storage instructions, particularly for perishables. The family should not buy food close to a use-by date simply because its unit price is attractive if there is no safe plan to consume it in time.

Do not freeze, repackage or reheat foods contrary to appropriate safety instructions. The household’s goal is better value and safe use, not forcing consumption of questionable products to defend an earlier purchase.

A useful family shopping budget

Start with a reasonable amount the household can spend and a short list of genuine needs. Use unit pricing to compare alternatives within that list. Avoid bringing children into an endless search for the mathematically cheapest item if it causes stress or encourages buying extras.

A small exercise can compare two rice packs and one household item. The family can then enjoy the rest of the trip. Financial literacy is the ability to make sensible choices, not a requirement to calculate every price in the supermarket.

The shopping trip can be a Primary Mathematics lesson

Ask a Primary 4 to 6 learner to identify the package size, price and standard unit for two comparable items. Let them convert grams to kilograms or millilitres to litres, then explain which has a lower unit cost. The child should show the calculation and write the unit beside the result.

Do not expect young pupils to understand complicated supplier promotions, taxes and product categories all at once. Start with simple labels and expand only when the learner is interested. The learning outcome is proportional reasoning in a familiar real-world situation.

A Secondary Mathematics extension

An older student can calculate percentage differences, investigate rounding and compare an offer with a household’s actual consumption. For example, if a hypothetical item costs S$0.80 per 100 grams at one shop and S$1.00 at another, the difference is S$0.20, or 20% of the S$1.00 benchmark.

The percentage depends on which price is used as the reference. Ask the student to state the denominator and avoid vague claims such as ‘25% cheaper’ without explaining the comparison. Good mathematics includes accurate wording.

A consumer-literacy extension

Look at what information the government pilot is trying to make easier to use. Shoppers can face confusing size choices, promotions and brands. A clear standard unit reduces one barrier to comparison, but it does not solve product quality or household needs.

Students can also discuss why a voluntary pilot gathers consumer feedback before broader decisions. Public information tools are designed and evaluated; their presence in a shop is not proof that every consumer will make the same best choice.

A Science extension: measurement units

Mass and volume measure different physical properties. A shopping shelf may display grams, millilitres, litres and counts. Explain why comparing price per litre of oil with price per kilogram of rice would not answer a sensible question about equivalent products.

Students can practise conversions where the relationship is defined, such as 1000 grams per kilogram. They should not assume the mass of one millilitre of every substance is one gram. Accurate measurement is a foundation of Science as well as consumer Mathematics.

The adult should remain responsible for purchasing

A child can help compare labels, but should not be asked to manage the household’s bank card or decide nutrition, allergy or financial matters beyond their age. The responsible adult should review the final selection and payment conditions.

Encourage questions rather than reward a child for persuading the family to buy the largest pack. A good outcome can be choosing not to purchase anything until the household uses what it already owns.

A hypothetical Waterway Point lesson

A family visiting Don Don Donki at Waterway Point checks a selected product category with a visible unit-price label if offered under the current pilot. They compare two actual alternatives available on the shelf, taking care not to reproduce prices from an old online article as current facts.

If the label is unavailable, they use the present packaging information or choose a different product. The family notes that CCS listed the location as a pilot participant, but does not assume every item is covered or that the store is always the cheapest in Punggol.

A hypothetical cooking-oil comparison

Suppose one 750-millilitre bottle costs S$4.50 and another one-litre bottle costs S$5.60. The first is S$6 per litre and the second S$5.60 per litre. The larger bottle is cheaper per litre in this invented example.

However, a household that rarely cooks with that oil may prefer the smaller quantity to reduce waste or storage inconvenience. The result should say both things: unit price favours the larger bottle, while practical purchase value depends on household use.

A hypothetical tissue comparison

Imagine a hypothetical package of 400 tissue sheets costing S$3.20 and another containing 600 sheets costing S$4.50. The first costs S$0.80 per 100 sheets, while the second costs S$0.75 per 100 sheets. That makes the second package cheaper on a quantity-only basis.

The family should still check ply, size and comfort. A lower price per sheet does not always represent better usable quality. This is a useful example of where mathematical comparison and product judgement work together.

A hypothetical promotion comparison

Suppose a single 500-gram product costs S$3, while a promotion offers two identical packs for S$5. The usual price is S$0.60 per 100 grams, while the bundle costs S$0.50 per 100 grams if the family genuinely buys and receives both packs.

Those are teaching figures, not a live promotion. If one pack will spoil, the extra purchase may cost more than it saves. Ask whether the family needs the full kilogram before deciding that the bundle is good value.

Do not use the wrong unit to declare a bargain

A common mistake is comparing a 750-gram item priced per kilogram against a 500-gram item priced per 100 grams without converting. The numbers may differ by a factor of ten, creating a false conclusion.

The remedy is simple: write the same unit next to both prices before comparing them. A child who notices mismatched units and stops the calculation has demonstrated better financial judgement than someone who quickly picks the wrong number.

Receipts can test the result

After an ordinary family purchase, compare the shelf price, any promotion terms and the amount charged on the receipt. If the calculation used a promotion requiring membership, check whether that condition actually applied. Keep the receipt private, especially if it contains payment identifiers.

Ask staff politely if there is a genuine discrepancy. Do not accuse a cashier of wrongdoing because a parent misread a pack size or forgot a promotional condition. A clear question and factual record are better than a confrontation.

An online comparison should include pack identity

The same brand can sell items in multiple sizes, variants and bundle formats. A search result might show a photograph of one package while the description lists another. Read the actual weight, volume or count and avoid comparing a different flavour or product type without noting the difference.

Some online platforms update prices quickly or offer member-specific conditions. Record the date of the comparison and do not publish the values as lasting Punggol retail prices. A calculation is only as current and correct as its inputs.

What if a product does not show the net amount?

Without reliable package quantity, a unit-price calculation may not be possible. Do not estimate kilograms from how heavy an item feels or claim a precise per-gram price from visual appearance. Ask the retailer for appropriate information or compare another clearly labelled product.

Learning to say ‘not enough data’ is part of consumer literacy. A child should not be pressured to invent a number just to complete the worksheet. Some products may be sold by item rather than mass or volume, which requires a different comparison.

The price label can be read as a data source

A shelf label has a current product identity, price, measurement and sometimes conditions. A family can ask which fields are directly observed and which are calculated. An official government pilot explains the standardisation, while a particular shelf gives the actual shop’s data at that moment.

Do not confuse a CCS explanatory example with a live quote. Source discipline matters even for groceries: an example teaches the formula, while a real purchase requires the present retailer’s terms.

The pilot’s consumer survey is optional

CCS describes consumer feedback surveys as part of evaluating the pilot. A person may be approached at participating outlets for an optional research interaction, but a family is not required to disclose personal financial information merely because a survey takes place nearby.

Check who is conducting any survey and what data are requested. Participation should be voluntary and informed. The family can enjoy using unit pricing without enrolling in a study.

Avoid shame when budgets differ

Different households have different income, storage, dietary and travel constraints. The option with the lowest unit price may require too much upfront spending, or a product may not fit a family’s needs. Children should not be taught that buying a smaller pack is irresponsible.

Use the lesson to show that constraints matter. Responsible consumer Mathematics respects people’s circumstances and avoids judging a neighbour’s choices from a single receipt.

What a successful fifteen-minute exercise produces

At the end, a child or adult can explain how to convert pack size to a common unit, compare two actual prices and name one practical limitation, such as likely consumption or product quality. The family does not need to purchase anything for the lesson to work.

That skill transfers to groceries, household supplies and online shopping. In Punggol, the October 2026 pilot gives a timely local connection, but the reasoning will remain useful even when individual retailers change their labels.

Frequently asked questions

What is unit pricing?

It is the price per standard amount, such as per kilogram, litre, 100 grams, 100 millilitres or item, allowing like-for-like cost comparisons.

When did Singapore’s expanded pilot start?

CCS says Stage 2 began on 1 October 2026, with participating retailers and selected online shops following their rollout schedules.

Is Don Don Donki Waterway Point included?

Yes. CCS lists its Waterway Point outlet at 83 Punggol Central among participating Don Don Donki pilot locations. Coverage is limited to selected categories.

Does every Punggol shop have unit pricing?

No. The 2026 arrangement is a pilot with operator, category and implementation differences. Check the actual label.

Does a larger pack always cost less per unit?

No. Compare the actual total price and quantity. Discounts, promotions and product differences can change the result.

How do I calculate price per 100 grams?

Divide the selling price by the number of 100-gram units in the package. A 500-gram package contains five such units.

Can I compare a price per kg with a price per 100g directly?

Convert to the same unit first. A per-kilogram price is ten times a per-100-gram price for the same item.

Is 1 litre equal to 1000 millilitres?

Yes. Use that conversion when comparing appropriate volume-based products.

Can I convert grams to millilitres automatically?

No. Mass and volume are different quantities; conversion depends on the substance’s density.

Are bundled promotions included in the calculation?

Use the real total paid and the total amount received under the actual offer conditions, including membership requirements.

Should I buy the biggest pack?

Only if it suits real consumption, storage, cash budget and product quality. Lower unit price alone may not produce better overall value.

What if the item expires before we use it?

Buying extra food that is later discarded can eliminate theoretical savings. Follow safe storage and date guidance.

Can price per sheet compare tissues?

It can compare quantity, but sheet size, ply and quality may still differ.

Is the cheapest per 100 grams necessarily healthiest?

No. Nutrition, allergens, ingredients and dietary requirements are separate from price.

Can I compare online listings?

Yes, but include actual size, promotion, delivery cost and membership conditions. Online prices may change.

What if a participating store has no unit-price label on a product?

Only selected categories may be covered. Use the actual selling price and package size for your own calculation if available.

Are these example prices real Punggol shelf prices?

No. All numerical product-price examples in the article are expressly hypothetical unless tied to a verified current retailer quote.

Can Primary pupils use this for Mathematics?

Yes. It develops ratios, measurement units and practical reasoning with age-appropriate supervision.

What does the pilot test?

CCS and CASE are gathering experience and consumer feedback on the usefulness of displaying unit prices across retailers and products.

What is the best result?

A correct equal-unit comparison and a sensible purchase decision that also considers the family’s actual needs.

Official sources and related Punggol reading

• CCS: About Unit Pricing and official participating outlets
• CCS: Stage 2 expansion from 1 October 2026
• CASE: Unit pricing guide for consumers
• CNA: September 2026 expansion report
• NEA: household food-waste prevention and buying only what is needed
• LifeSG and government consumer information
• eduKate Punggol: seven-day household food-waste challenge
• eduKate Punggol: compare a Punggol hawker meal
• eduKate Punggol: family money-smart shopping overview

Editorial verification: 31 October 2026. Unit pricing remains a staged pilot and coverage may vary by category, outlet and platform. Product examples and promotions are hypothetical, not current quotes from Punggol retailers. Check actual shelf or checkout information, food safety and household needs before purchasing. Follow CCS and CASE for official pilot updates.