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CC.4 Multiply and divide money: word problems

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Multiplying and dividing money in word problems

Multiplying money involves finding the total cost when you have multiple items at the same price. Dividing money involves splitting a total amount into equal parts or finding the cost of one item when you know the total cost for multiple items.

Examples:
  • Question: If one notebook costs $1.25, how much do 4 notebooks cost?
    Solution: $1.25 × 4 = $5.00
  • Question: If 3 identical toys cost $8.97, what is the price of one toy?
    Solution: $8.97 ÷ 3 = $2.99
  • Question: A school club raised $42.36 from 6 students selling equal amounts of candy. How much did each student raise?
    Solution: $42.36 ÷ 6 = $7.06
Note

Always include the dollar sign ($) and decimal point in your answers when working with money. The decimal point separates dollars from cents.

Setting up money multiplication problems

When multiplying money, you multiply the dollar amount just like regular numbers, but you must keep track of the decimal point representing cents.

Steps with Example:
  • Identify the cost of one item and how many items you need
    Example: One pencil costs $0.89, need 7 pencils
  • Write the multiplication problem with the dollar amount
    Example: $0.89 × 7
  • Multiply as with regular numbers, aligning decimal points
    Example: 89 × 7 = 623, then place decimal: $6.23
  • Include the dollar sign in your final answer
    Example: Total cost = $6.23
Note

When multiplying money, the decimal point in your answer should have two digits after it to represent cents, even if they are zeros.

Solving money division problems

Division with money helps you find equal shares or unit prices. You divide the total amount by the number of items or people.

Examples with Solutions:
  • Formula: Total cost ÷ Number of items = Cost per item
    Example: $15.84 ÷ 4 = $3.96
  • Formula: Total money ÷ Number of people = Equal share for each
    Example: $27.93 ÷ 3 = $9.31
  • Real Problem: Five friends want to buy a game that costs $34.95. How much will each pay if they split the cost equally?
    Solution: $34.95 ÷ 5 = $6.99
Note

When dividing money, you may need to add zeros after the decimal point to complete the division. Continue dividing until you have exactly two decimal places for cents.

Real world applications

Multiplying and dividing money skills are used in everyday situations like shopping, splitting costs, and fundraising.

Real Situations with Solutions:
  • Shopping: You need 8 batteries that cost $2.37 each. What is the total cost?
    Solution: $2.37 × 8 = $18.96
  • Splitting Bills: Four friends share a pizza that costs $21.48. How much does each pay?
    Solution: $21.48 ÷ 4 = $5.37
  • Bulk Buying: A pack of 6 juice boxes costs $4.74. What is the price per juice box?
    Solution: $4.74 ÷ 6 = $0.79
  • Fundraising: Sarah sold 9 raffle tickets at $1.25 each. How much money did she collect?
    Solution: $1.25 × 9 = $11.25
Note

Always check if your answer makes sense. If you're finding the cost of one item, it should be less than the total cost. If you're finding the total cost, it should be more than the cost of one item.

Checking your work

Verifying your calculations ensures accuracy when working with money. Use inverse operations to check your answers.

Verification Methods with Examples:
  • For multiplication: Check by dividing your answer by the number of items
    Example: If $2.38 × 5 = $11.90, then $11.90 ÷ 5 should equal $2.38
  • For division: Check by multiplying your answer by the number of items
    Example: If $18.72 ÷ 8 = $2.34, then $2.34 × 8 should equal $18.72
  • Estimation: Round numbers to check reasonableness
    Example: $3.17 × 6 is about $3 × 6 = $18, so $19.02 is reasonable
Note

If your check doesn't bring you back to the original numbers, recheck your calculations. Pay special attention to decimal placement.