Solve problems involving money.
Solve multi-step real-world problems involving money using decimal notation. Example: Don is at the store and wants to buy soda. Which option would be cheaper: buying one 24-ounce can of soda for $1.39 or buying two 12-ounce cans of soda for 69¢ each?
Purpose and Instructional Strategies
The purpose of this standard is for students to apply understanding of multi-step real-world problems, measurement conversions, and decimal operations to solve problems involving money (MTR.7.1). This benchmark connects to previous work in Grade 4 where students added and subtracted money in real world situations (MA.4.M.2.2). Money contexts continue to be important throughout the later grades.
During instruction, teachers should provide strategies for helping students comprehend what is happening in the problem and what needs to be found before students complete numerical calculations. Students should be encouraged to estimate a solution and model a problem using manipulatives, pictures and/or equations before computing (K12.MTR.2.1).
Common Misconceptions or Errors
Students can misinterpret multi-step word problems and only complete one of the steps. Encourage students to estimate reasonable solutions and justify models to solve before computing.
Instructional Task 1
Jordan was saving his money to buy a remote control motorcycle. He saved $37.81 from his allowance and received two checks worth $10.00 each for his birthday. Jordan also has a half dollar coin collection with 30 coins in it. If the motorcycle costs $72.29, does Jordan have enough money to buy the motorcycle?
Instructional Item 1
Pecans and almonds each cost $6.80 per pound. Kendall buys 1.5 pounds of pecans and 2.5 pounds of almonds. What is the total cost of Kendall’s purchase?
Instructional Item 2 A table below shows the costs of items at a candy store.
Wayne has $10 to spend. Select all the purchases that Wayne has enough money to make.
a. 3 chocolate bars
b. 25 ounces of candy rope
c. 2 chocolate bars and 3 peanut butter cups
d. 3 peanut butter cups and 5 ounces of bubble gum
e. 24 ounces of bubble gum and 2 ounces of candy rope