Equivalent forms: Percent, Fraction, and Decimal

Converting and equivalent forms

Fractions, decimals, and percents are all equivalent ways of writing the same ratio. Percent means “per 100” or “out of 100”, so we are really just finding an equivalent ratio where the “whole” amount is 100.

Example: You brought 20 cookies to your math class to share and everyone got 2 cookies. If you had brought 100 cookies, how many would each person get?

We could write this as $\frac{2}{20}$ or if we multiply by 5, $\frac{10}{100}$ .

We could also represent this as a decimal.

$\frac{2}{20}$ = 0.1 because we can divide top and bottom by 2 to get $\frac{1}{10}$ , which is one tenth.

Sometimes we will have percent as a decimal and want to convert it to a fraction. This is often as simple as looking at the place of the last digit of the decimal and writing it as a fraction over that number of zeros.

Example: Convert 0.34 to a fraction

What place is the 4 in? It is in the hundredths place

Write 34 as a fraction over 100: $\frac{34}{100}$ If you would like, this can be simplified to $\frac{17}{50}$

Glencoe 5-2
- Percents as decimals
- Decimals as percents
- Fractions as percents
- Ordering different forms of percents
- Assignment: P. 259 (13-57 odd)

Working with percent

Glencoe 5-3
- Percent proportion
- Finding percent, part, and whole
- Percents greater than 100
- Assignment: P. 266 (11-25 all)