Multiplying related sets of numbers illustrates how the number of decimal places in the factors relates to the number of decimal places in the product. Finding numbers with a given product helps you develop a deeper understanding of multiplication. The typical situations of discounts, taxes, and tips to help students think about taking a percent of a number. The discount and tax situations help students to consider the amount left when a reduction is made and the total when taxes are added. In this investigation students are asked to think about percents in situations in which the number of objects is greater than or fewer than 100.
Students use percents to help construct and make sense of circle graphs.
This investigation focuses on estimating sums of fractions and decimals. Students play two games in which they use benchmarks to help them estimate how big sums are. This investigation does not give students algorithms for computation. Instead, it prepares students to figure out how to add and subtract fractions by emphasizing flexibility in finding equivalent fractions and in changing between fractions and decimals. In the course of struggling with the problems, most students will invent ways of adding fractions that you and the class can help make more explicit and efficient.