Classroom Store Lab

Run your own classroom store. Browse items with price tags, calculate totals using coins and bills, make exact change, and track every purchase in a data table.

Guided Experiment: Running the Classroom Store

If you had $5 to spend at the store, which items would you choose? Predict the total cost and how much change you would receive.

Write your hypothesis in the Lab Report panel, then click Next.

Controls

Choose an Item

Purchase: ✏️ Pencil$0.25 each

Quantity1
Total Cost$0.25
Choose Payment
Change$0.75
3 quarters

Data Table

(0 rows)
#ItemPriceQuantityTotal CostPaymentChange
0 / 500
0 / 500
0 / 500

Reference Guide

Coin and Bill Values

Penny
1 cent = $0.01
Nickel
5 cents = $0.05
Dime
10 cents = $0.10
Quarter
25 cents = $0.25
Dollar Bill
100 cents = $1.00
Five Dollar Bill
500 cents = $5.00

Calculating Totals

To find the total cost of several of the same item, multiply the price by the quantity.

Total = Price × Quantity

Example: 3 pencils at $0.25 each

$0.25 × 3 = $0.75

Always line up the decimal points when adding money amounts.

Making Change

Change is the amount you get back when you pay more than the price.

Change = Payment - Total Cost

Count-up strategy: start at the price and count up to the payment amount.

Example: Item costs $0.75. You pay $1.00.

$1.00 - $0.75 = $0.25 change

Staying on Budget

A budget is the most money you can spend. Keep a running total as you shop.

Add up all item totals and compare to your budget:

Remaining = Budget - Total Spent

If the remaining amount is positive, you are within budget. If it is negative, you have overspent.