SSAT Middle Level Math : How to subtract fractions

Study concepts, example questions & explanations for SSAT Middle Level Math

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Example Questions

Example Question #1 : Subtracting Mixed Numbers

Solve the following: 

\(\displaystyle 43\frac{5}{9}-37\frac{4}{9}\)

Possible Answers:

\(\displaystyle 7\frac{1}{9}\)

\(\displaystyle 6\frac{1}{8}\)

\(\displaystyle 6\frac{1}{9}\)

\(\displaystyle 7\frac{1}{8}\)

\(\displaystyle 6\frac{2}{9}\)

Correct answer:

\(\displaystyle 6\frac{1}{9}\)

Explanation:

When we subtract mixed numbers, we subtract whole numbers by whole numbers and fractions by fractions. 

\(\displaystyle 43-37=6\)

\(\displaystyle \frac{5}{9}-\frac{4}{9}=\frac{1}{9}\)

Remember, when we are subtracting fractions we must have common denominators and we only subtract the numerators. 

Example Question #61 : Solve Word Problems Involving Addition And Subtraction Of Fractions: Ccss.Math.Content.4.Nf.B.3d

A baker used \(\displaystyle \frac{1}{7}\) of a pound of sprinkles and \(\displaystyle \frac{6}{7}\) of a pound of icing when decorating a cake. How much more icing than sprinkles did the baker use, in pounds?

Possible Answers:

\(\displaystyle \frac{4}{7}\)

\(\displaystyle \frac{6}{}7\)

\(\displaystyle \frac{5}{7}\)

\(\displaystyle \frac{2}{7}\)

\(\displaystyle \frac{3}{7}\)

Correct answer:

\(\displaystyle \frac{5}{7}\)

Explanation:

The phrase, "how much more" tells as that we want to find the difference, so we subtract. 

\(\displaystyle \frac{6}{7}-\frac{1}{7}=\frac{5}{7}\)

5 7

Example Question #111 : How To Subtract Fractions

Shannon has painted \(\displaystyle \frac{5}{8}\) of the house and Dan has painted \(\displaystyle \frac{1}4{}\) of the house. How much more of the house has Shannon painted?

Possible Answers:

\(\displaystyle \frac{3}{8}\)

\(\displaystyle \frac{3}4{}\)

\(\displaystyle \frac{5}7{}\)

\(\displaystyle \frac{1}4{}\)

\(\displaystyle \frac{9}{11}\)

Correct answer:

\(\displaystyle \frac{3}{8}\)

Explanation:

\(\displaystyle \frac{5}{8}-\frac{1}{4}\)

In order to solve this problem, we first need to make common denominators. 

\(\displaystyle \frac{1}{4}\times\frac{2}{2}=\frac{2}{8}\)

Now that we have common denominators, we can subtract the fractions. Remember, when we subtract fractions, the denominator stays the same, we only subtract the numerator. 

\(\displaystyle \frac{5}{8}-\frac{2}{8}=\frac{3}{8}\)

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