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Fraction Classroom · 2.4.0 · Student pages

Repair a receipt and verify the change

Trace a subtotal error through a payment record, correct it and use the payment equation to verify the change.

Anonymous group code: __________   Date: __________

The corrected item record accounts for both pencils before finding change from the stated payment.ItemQuantityEachLine totalNotebook1$1.25$1.25Pencil2$0.40$0.80Correct subtotal$2.05
The corrected item record accounts for both pencils before finding change from the stated payment.

Build the idea

model. A receipt lists a notebook at $1.25 and two pencils at $0.40 each, then claims a $1.65 subtotal and $1.35 change from $3.00. Repair it.

  1. Read quantity and price separately. The notebook is one item at $1.25, while two pencils each cost $0.40; the pencil line must include two equal prices.
  2. Calculate the line totals, then add equal place-value units: $1.25 + $0.80 = $2.05. Keep the cents column aligned even when a price is written with one decimal digit.
  3. Subtract the corrected subtotal from the $3.00 payment to obtain $0.95 change. Updating only the subtotal would leave the receipt inconsistent.
  4. Check both the arithmetic and the item record. $2.05 + $0.95 = $3.00, and the subtotal includes all three items. A payment check alone cannot reveal an omitted item if subtotal and change share the same error.

Worked example: The pencils cost $0.80 together. The correct subtotal is $2.05, and the correct change is $0.95. The incorrect receipt counted only one pencil.

Practise and explain

Try p1–p3 with a partner. Use a drawing and label your units. Try e1 independently before comparing responses.

p1. Three erasers cost $0.35 each. Enter the correct line total in dollars.

p2. One item costs $1.60 and another costs $0.75. Enter their subtotal in dollars.

p3. The correct subtotal is $2.35 and the payment is $5.00. Enter the change in dollars.

e1. A notebook costs $2.20 and two clips cost $0.45 each. You pay $4.00. Enter the correct change in dollars and write the item subtotal.

Transfer the idea

transfer. A second receipt lists one $0.60 item and one $0.25 item as a total of $0.31. Explain a likely place-value error and state the correct subtotal.