Ratio and Proportion Cheat Sheet
1. Writing a Ratio:
a. The quantity written first is the numerator
b. The word “to” separates the quantities
c. The quantity written second is the denominator
d. Always write in lowest terms, and always as a fraction
Example: Write the ratio of 60 days of sun to 20 days of rain.
e. Ratios are written with LIKE terms
Example: 2 days to 8 hours
*2 days = 48 hours
2. Using Mixed Numbers in Ratios:
a. Write out the ratio
b. Write numbers as improper fractions
c. Rewrite the problem horizontally, using the ÷ symbol
d. Change the ÷ to × and flip the second term
Example: 2 days to 21
4 days
3. Writing Rates:
*Units are not the same and need to be included as part of the rate*
a. Write the rate as a fraction in lowest terms
Example: 160 dollars for 8 hours
÷ 2
60
20 =30
10 =3
1
÷10
leave as a fraction
48
8=6
1
÷ 8
2
21
4
=
2
1
9
4
=2
1÷9
4=2
1×9
4=8
9
lowest terms
160 𝑑𝑜𝑙𝑙𝑎𝑟𝑠
8 ℎ𝑜𝑢𝑟𝑠 =20 𝑑𝑜𝑙𝑙𝑎𝑟𝑠
1 ℎ𝑜𝑢𝑟
