Money totals and change

Work in the same unit

A notebook costs $4.75 and a pen costs $2.60. In cents, the cost is 475 + 260 = 735 cents, or $7.35.

You can also add the money notation in columns. Line up the dots: dollars under dollars, tenths of a dollar under tenths, and hundredths under hundredths. The 75 cents and 60 cents make 135 cents: exchange 100 cents for a dollar.

Adding the dollars without the exchanged dollar would give $6.35 and lose part of the amount.

When an answer is requested in dollars with two decimal places, write both digits after the point: $2.60 names two dollars and sixty cents. $2.6 is the same amount, but it does not show the requested two-place notation. Keep the unit clear: 735 cents is $7.35, not $735.

Check your understanding 1 Add the amounts and keep the unit

Two items cost $2.85 and $1.70. Find their total in dollars, using two decimal places. Use cents to check your result.

Your total in dollars and check in cents, or work on paper

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The total is $4.55. In cents, 285 + 170 = 455. The 85 cents and 70 cents make 155 cents: exchange 100 of them for another dollar and leave 55 cents.

Change is a missing part

You pay $10.00 for the two items. Find the amount left from the payment:

The change is $2.65. Check $7.35 plus $2.65 makes $10.00.

A counting-up method agrees: from $7.35 add 65 cents to reach $8.00, then $2.00 to reach $10.00. The added amounts total $2.65.

Check your understanding 2 Calculate, then check

An item costs $6.85. You pay $10.00. How many cents should you receive as change?

Change in cents

Check answer

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315 cents, or $3.15. The payment is the whole; cost and change are its two parts.

Check your understanding 3 Find a price from the change

Two items are bought with $20.00. The change is $4.35 and one item costs $8.70. What is the price of the other item?

Your price, working and check, or work on paper

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The items cost 2000-435 = 1565 cents altogether. The other item costs 1565-870 = 695 cents, or $6.95. Check $8.70 + $6.95 + $4.35 = $20.00. Subtracting the known price from the payment before accounting for change would overstate the unknown price.

Estimate to catch a misplaced digit

A price near $7 and another near $3 should give a total near $10, not $1 or $100. Use an estimate to check the scale, then keep the exact cents in your answer.