Lesson 4-2 Making Estimates for Products Overview: Students make estimates and evaluate the reasonableness of their answers.

Math Message Math Masters page 147 – on board

Math Message – Follow up Turn to page 286 in your SRB Does any of this information surprise you? Do you think any of this information has changed since it was collected? What is meant by the “average” amount of food per year? Does everyone eat more than 2,000 pounds of food per year; or about 5½ pounds per day?

Today you will be estimating the products of large numbers Today you will be estimating the products of large numbers. You can use front-end estimation, close-to estimation, or you can round the numbers.

Things to consider when estimating … ask yourself Is my answer reasonable? Is my estimate and the real answer close? A wide range of estimates can come from using different estimation strategies. Some strategies aren’t as precise as others.

Back to the answers from the math message Using your answers from the math message, compare your consumption of certain foods to the average for Americans. Convert your weekly results of 1 year totals. Multiply the total amount eaten in 1 week by 100. This gives an estimate of the total amount eaten in 100 weeks, which is about 2 years. Divide the result by 2, or find half of your answer. This gives an estimate of the total amount eaten in about 1 year. Record your 1 year totals on your slate.

Work on math journal page 108 Work on math journal page 108. These are multi-step, multidigit multiplication problems. Estimate first. Then … use a calculator to compare the reasonableness of your estimated answer.

About how many pounds of bananas might the students in our class eat in 1 year? About how many eggs might an average family of four eat in 1 year? About how many cups of milk might all the fourth-grade students in our school drink in 1 year?

Summary / Exit Ticket What are some real life situations in which estimates of counts are used.