5th Grade Multiplying Fractions and Mixed Numbers Quiz: 10 Questions with Explanations

A \(\frac{5}{7}\)B \(\frac{1}{12}\)C \(\frac{1}{2}\)D \(\frac{3}{4}\)

The overlap has 6 of 12 squares: 6/12 = 1/2. Adding the fractions would give a number greater than 1, not 5/7.

A \(\frac{8}{12}\)B \(2\frac{2}{3}\)C \(4\frac{2}{3}\)D \(\frac{2}{12}\)

Write 4 as 4/1: 8/3 = 2 2/3. A common mistake is to multiply the denominator by 4 as well.

A \(\frac{1}{2}\)B \(\frac{8}{11}\)C \(\frac{18}{25}\)D \(\frac{3}{5}\)

3 x 5 = 15 and 5 x 6 = 30, so the product is 15/30 = 1/2. Adding numerators and denominators gives 8/11, which is wrong.

A 50B 4C 12D 8

Each part is 20 / 5 = 4. Two parts make 8. Saying 50 comes from multiplying 20 by 5/2, which is the wrong direction.

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

3/2 x 2 = 6/2 = 3. Multiplying only the whole part gives 2 1/2.

A \(2\frac{1}{6}\)B \(3\frac{5}{6}\)C \(4\frac{1}{2}\)D \(3\frac{1}{2}\)

7/3 x 3/2 = 21/6 = 3 1/2. Multiplying wholes and fractions separately gives 2 1/6, which is wrong.

A \(\frac{1}{2}\) cupB \(\frac{1}{12}\) cupC \(\frac{17}{12}\) cupD \(\frac{5}{12}\) cup

3/4 x 2/3 = 6/12 = 1/2. Adding the fractions gives 17/12, and subtracting gives 1/12.

A \(3\frac{3}{4}\) square feetB \(2\frac{3}{8}\) square feetC \(3\frac{3}{8}\) square feetD \(3\frac{1}{8}\) square feet

9/4 x 3/2 = 27/8 = 3 3/8. Adding the sides gives 3 3/4, which is not the area.

A 16B 9C 3D 15

12 / 4 = 3, and 3 x 3 = 9. Dividing 12 by 3/4 gives 16, which is the wrong operation.

A 15B 3C 12D 90

Each group has 18 / 6 = 3 stickers. Five groups make 15.