Firing up Fourth

          Students will be studying rates, the most common applications of mathematics in daily life. A rate is a comparison involving two different units. Familiar examples come from working (dollars per hour), driving (miles per hour), eating (calories per serving), reading (pages per day), and so on. Students will collect data on the rate at which their classmates blink their eyes. The class will try to answer the question, "Does a person's eye-blinking rate depend on what the person is doing?" Together we will develop strategies for solving rate problems. 

           This unit emphasizes the importance of mathematics to smart consumer. Your child will learn about unit-pricing labels on supermarket shelves and how to use these labels to decide which of two items is the better buy. Your child will see that comparing prices is only part of being a smart consumer. Other factors to consider include quality, the need for the product, and perhaps the product's effect on the environment.

            This unit provides a great opportunity for your child to help with the family shopping. Have your child help you decide whether the largest size is necessarily the best buy. Is an item on sale necessarily a better buy than a similar product that is no on sale? 

Vocabulary

Comparison shopping, consumer, per, rate, rate table, unit price, unit rate 

Objectives

  • Find unit rates.

  • Calculate unit prices to determine which product is the "better buy."

  • Evaluate reasonableness of rate data.

  • Collect and compare rate data.

  • Use rate tables, if necessary, to solve rate problems.

Games

  • Credits/Debits Game - Advanced: This game for 2 players simulates bookkeeping for a small business. A deck of number cards represents "credits" and "debits." Transactions are entered by the players on recording sheets that are easily drawn. The game offers practice in addition and subtraction of positive and negative integers. 

Activities

  • Have your child examine the Nutrition Facts labels on various cans and packages of food. The label lists the number of servings in the container and the number of calories per serving. Have you child use this information to calculate the total number of calories in the full container or food.

  • Have your child point out rates in every day situations. For example: store price rates: cost per dozen, cost per 6-pack, cost per ounce; rent payments: dollars per month, or dollars per year; fuel efficiency: miles per gallon; wages: dollars per hour; sleep: hours per night; or telephone rates: cents per minute.

  • Use supermarket visits to compare prices for different brands of an item and for different sizes of the same item. Have you child calculate unit prices and discuss best buys.