Fractions, Decimals and Percents with Area
In this lesson, we use some of the area concepts from past lessons to connect fraction, decimal and percent representations of number. By using a transparent 1-CM grid, students can determine the area of irregular shapes in square CM. Then, by defining 1 square 'unit' to be a 10-by-10 grid, the areas can be represented as fractions, decimals and percents of the 10-by-10 'unit'.
(Click here to see how to determine the area of the above shape.)
Once the area of the shape has been determined, then we can restate the number as a fraction, decimal, or percent of the 'unit'.
26.5 square cm out of the 10-by-10 grid 'unit' would be 26.5/100 (or 265/1000) as a fraction, and .265 as a decimal. Since the 10-by-10 grid also represents 100%, the fraction could be written as 26.5% of the 'unit'.
By exploring the areas of a variety of shapes and their number representations, students review and solidify some area concepts, as well as become comfortable with the various relationships between fractions, decimals, and percents. These relationships will be further applied in the next lesson on Probability and Fair Games.