M3.3.8 For the adult

Percentages

What does 35% mean, and what is 15% of 80?

What this chapter teaches

A percentage is a fraction out of 100. It is changed into a fraction by writing it over 100 and simplifying, and into a decimal by dividing by 100. To find a percentage of an amount, build it from 10%, 5% and 1%. To write one amount as a percentage of another, make the bottom of the fraction 100.

Three questions to ask

There is no one right wording. Listen for the idea.

  1. What does 35% mean, and how do you write it as a decimal?
  2. How can you find 15% of 80 without a calculator?
  3. How do you write 18 out of 50 as a percentage?

After the chapter, the learner can

  • Write 35% as a fraction and as a decimal
  • Find 15% of 80 by finding 10% and 5%
  • Write one amount as a percentage of another

What they copy into their notebook

Percent means out of 100. 35% = 35/100 = 0.35. To find 15%, find 10% by dividing by 10, then 5% as half of that, and add.

Back to the chapter