Lesson: Using proportions to convert fractions and percents
Do Now: (5 minutes)
1) Write 25% as a fraction and decimal.
2) Write 0.4 as a fraction and a percent.
3) Write 3/8 as a decimal and a percent.
Direct Instruction: (20 minutes)
How are fractions, decimals, and percents the same? Let's take a look at the work that we did on our do now problems. (Go over method for each problem as a class). Today we are going to continue to work with fractions and percents. We are going to bring together our knowledge of converting fractions and percents and proportions. Let's take a look at how that works.
What does percent mean? (Out of 100). So what do we think we will need as part of our proportion?
Ex. Convert 4/15 to a percent.
Carefully go through the steps as a class with students writing the work in their notes. When the problem is completed, review the steps together and add them to the notes.
To write a fraction as a percent:
1) Set up a proportion. One ratio is the fraction. The other ratio is a variable over 100.
2) Use cross multiplication to complete the proportion.
Remind students that part is across from part, whole is across from whole.
Ex. Convert 7/30 to a percent.
E. Convert 1 3/11 to a percent.
If I have one whole, what is that in percents?
Guided Practice: (10 minutes)
Ex. Convert 12/35 to a percent
Ex. Convert 8/45 to a percent
Ex. Convert 2 14/27 to a percent
Assessment: (10 minutes)
Converting fractions to percents work-out
|fractions to percents work out Assessment||