4th Grade Adding and Subtracting Fractions and Mixed Numbers Quiz: 10 Questions with Explanations

A \(\frac{5}{8}\)B \(\frac{5}{16}\)C \(\frac{1}{8}\)D \(\frac{6}{8}\)

Add the numerators and keep the denominator: 3 + 2 = 5. Adding the denominators is the common mistake.

A \(\frac{6}{0}\)B \(\frac{6}{10}\)C \(\frac{12}{10}\)D \(\frac{6}{20}\)

Subtract the numerators: 9 – 3 = 6. The denominator stays 10.

A \(\frac{2}{6} + \frac{3}{6} = \frac{5}{6}\)B \(\frac{2}{6} + \frac{3}{6} = \frac{5}{12}\)C \(\frac{2}{6} + \frac{3}{6} = \frac{6}{12}\)D \(\frac{2}{6} + \frac{3}{6} = \frac{1}{6}\)

2 sixths and 3 sixths make 5 sixths. The denominator does not change.

A \(\frac{2}{8} + \frac{2}{8}\)B \(\frac{2}{8} + \frac{3}{8}\)C \(\frac{3}{8} + \frac{3}{8}\)D \(\frac{4}{8} + \frac{4}{8}\)

2 + 3 = 5 eighths. The others make 4, 6 and 8 eighths.

A \(\frac{6}{3}\)B \(\frac{5}{3}\)C \(\frac{21}{3}\)D \(\frac{7}{3}\)

2 = \(\frac{6}{3}\), and \(\frac{6}{3}\) + \(\frac{1}{3}\) = \(\frac{7}{3}\). Forgetting the extra third gives \(\frac{6}{3}\).

A \(\frac{7}{4}\)B \(\frac{8}{4}\)C \(\frac{9}{4}\)D \(\frac{12}{4}\)

There are 2 full strips (8 fourths) and 1 more fourth, which is 9 fourths.

A \(3\frac{7}{10}\)B \(4\frac{1}{5}\)C \(3\frac{2}{5}\)D \(4\frac{2}{5}\)

Wholes: 1 + 2 = 3. Fractions: \(\frac{3}{5}\) + \(\frac{4}{5}\) = \(\frac{7}{5}\) = 1 \(\frac{2}{5}\). Total 4 \(\frac{2}{5}\).

A \(4\frac{1}{3}\)B \(3\frac{1}{3}\)C \(3\frac{2}{3}\)D \(4\frac{2}{3}\)

6 \(\frac{1}{3}\) = \(\frac{19}{3}\) and 2 \(\frac{2}{3}\) = \(\frac{8}{3}\). \(\frac{19}{3}\) – \(\frac{8}{3}\) = \(\frac{11}{3}\) = 3 \(\frac{2}{3}\).

A \(\frac{5}{8}\)B \(\frac{3}{8}\)C \(\frac{1}{8}\)D \(\frac{5}{16}\)

The whole is \(\frac{8}{8}\). \(\frac{8}{8}\) – \(\frac{5}{8}\) = \(\frac{3}{8}\). The \(\frac{5}{8}\) is how much was eaten.

A \(2\frac{2}{3}\) cupsB \(3\frac{1}{3}\) cupsC \(2\frac{1}{3}\) cupsD \(3\frac{2}{3}\) cups

4 \(\frac{1}{3}\) = \(\frac{13}{3}\) and 1 \(\frac{2}{3}\) = \(\frac{5}{3}\). \(\frac{13}{3}\) – \(\frac{5}{3}\) = \(\frac{8}{3}\) = 2 \(\frac{2}{3}\).