Activity Overview:

Time: 20-30 minutes
Materials: Pencil, grocery store flyer or receipt (or phone to look up prices), calculator (optional)
What: Your family compares two or three versions of the same grocery item, like different brands or sizes, by calculating the price per unit and deciding which is the best value.
Why: Unit rate is one of the most practical math skills anyone can use. Understanding how to fairly compare prices (not just total cost, but cost per ounce, per item, or per serving) helps with shopping, budgeting, and making smart decisions every day.

How to do it:

1. Pick an item: Choose something you buy regularly, like cereal, juice, rice, or shampoo. Find two or three versions with different sizes or brands.
2. Record prices: Write down the total price and the amount (ounces, count, or liters) for each option.
3. Calculate the unit rate: Divide the total price by the amount. Example: $3.60 for 12 oz = $0.30 per oz. Do this for each option.
4. Compare and decide: Which has the lowest price per unit? Is that the one you’d buy? Are there other factors like quality, household preferences, or expiration date that might change your choice? 5.Reflect: Ask “Did the biggest package always win?” “Were you surprised by any result?”

Tips:

Let your child be the “calculator person” even if they need to work slowly. The process matters more than speed.
Ask: “If we doubled the recipe, would we need to buy two of the small or one of the large? Which costs less?”

For more family math activities go to familymath.org.