How to Convert Percentages to Fractions and Decimals
Students can learn how to convert percents to decimals and fractions using 10x10 grids.
By Christina Lee
As educators, one of the most important lessons we ought to teach students is that of making connections. In mathematics, we can help students make connections between a concept and its real-life application. By doing this, we make information relevant, and help ensure that information will be understood and remembered. Percents, decimals and fractions are connected—they are simply different ways of expressing the same thing. Students also need to realize that percents, decimals, and fractions are present in real-life situations.
I always begin a lesson introducing students to percents by asking them to identify real-life situations in which they would find percents. For example, percents are used as part of test grades, or in nutritional information found on the back of cereal boxes. Students always love sharing their experiences with one another. It is important to engage students so that they understand that what they learn in school is not distinct or separate from what they encounter daily.
A visual representation of a very common fraction would be a great way to start the lesson. Many students are familiar with ½--they know how to model it visually and often understand that it is the same as 50%. A 10x10 grid is an excellent way to model this problem. I ask students to show me what they know by showing 50% on a 10x10 grid. Many students will be able to do this because of their background knowledge of ½. Then, students convert 50% to a decimal and fraction. If necessary, they count 50 shaded units of out of the 100 units to show 50/100 or ½. From there, students will be asked to count 50 blocks, or “fifty hundredths” in decimal form. This is a great opportunity to show students that all this is the same amount, but it is expressed different ways.
However, when it comes to certain percentages, such as 88%, that’s when it gets tricky. How would it be represented as a fraction? What about as a decimal? Students need to talk about it, see visual representations of 88%, 0.88, and 88/100, and, most importantly, practice making conversions. Here are some suggested lessons that would be ideal for students in the fifth and sixth grades.
Converting Percentages to Fractions, and Percentages to Decimals:
This is an excellent first activity to kick-off a unit on percents, fractions and decimals. Students are asked to consider real-life uses of percents, fractions, and decimals. Then, they compare how they are alike or different. This lesson is also great because it also gives options for differentiation.
Convert Percents, Decimals and Fractions with a Visual
This is an excellent visual representation of percents, decimals and fractions. It allows students to work with very basic fractions, such as ½ and so on. How to figure out and convert ½ back and forth is a fundamental concept in understanding more challenging problems.
Students need to be given an opportunity for hands-on practice with any math concept, especially percents, decimals, and fractions. Students color in the boxes in a 10x10 grid, and determine percent, decimal, and fraction based on the shaded units.
This is a simple, but useful, interactive web-based tool to practice conversions. Students put in their answer, and hit submit to see how they did. Anytime students are given the opportunity to do math at a computer, they seem more motivated to find the correct answer.
This is a simple worksheet with instructions for students to use for converting percents to fractions.
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