# 3rd Grade - Divide Total Cost To Find Cost Of One

 Grade Level: 3rd Skill: Multiplication and Division Topic: Divide Total Cost to Find Cost of One Goal: Determine the unit cost when given the total cost and number of units Skill Description: Number Sense: division with money The ability to solve a problem and come up with the unit cost (price per item) when the total cost of a group of items is given and the number of units purchased is given.

## Building Blocks/Prerequisites

### Sample Problems

 (1) What operation is used to solve a problem in which you want to know the cost of each object if you know the total cost of a group of objects and you know how many objects were purchased? (division) (2) Is estimation valuable in problems such as these? (yes, estimation can help us know if the answer is reasonable) For example, if the total cost is about \$24 and 6 units were sold, the answer should be about \$4 per unit. (3) The market is a great place to practice division with money concept. If a child buys 3 organic apples for \$.40 each, how many can be bought for \$3.00? (7) Will it always come out exactly when spending money? (No, sometimes you may spend less than you have, but always make sure to round up, so you don’t get stuck having to pay more than you have.) (4) Children can learn how to count back money as if the child was a cashier at a store. Start with the amount the customer paid and count back up to the dollar amount that was given. For example, if the customer bought items that cost \$4.25 and paid with a ten-dollar bill, the child can start counting by saying \$4.25. Then the child can add three quarters and say \$4.50, \$4.75, \$5.00 and then add another \$5 or five ones and count back up to \$10.00. (5) Understand that division of money is used in every day life: If the child is not sure about how to solve a problem, draw a picture. For example, Janet must pay \$20.00 for each of 4 tickets to a concert. She wants to know how much cash to bring to the ticket booth. The child may want to draw 4 tickets (rectangles) and label each one with a 20. The child can then skip count by 20s as they count the 4 tickets. 20, 40, 60, 80 or the child may write the number 20 in each ticket and use it like an equation 20 + 20 + 20 + 20 = 80.

### Online Resources

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