Multiplying mixed numbers - find the mistakes

​Find the mistake

By Mr. Lee

Find the mistake

There are 12 problems with answers.

Many of the problems have answers that are incorrect. You need to figure out what is wrong with the answer, and then figure out what the correct answer should be. Good luck!

Open Ended

Problem 1:

$$2\ \frac{1}{3}\ •\ 1\ \frac{1}{2}\ \ =\ 2\ \frac{1}{6}$$

Is this answer wrong? If so, what did they do wrong?

Multiple Choice

Problem 1:

$$2\ \frac{1}{3}\ •\ 1\ \frac{1}{2}\ \ =\ 2\ \frac{1}{6}$$

What is the correct answer?

• 3 1/2
• 2 1/4
• 3 3/4
• 1 1/2

Open Ended

Problem 2:

$$3\ \frac{3}{4}\ •\ \ 2\ \ =\ 6\ \frac{3}{4}$$

Is this answer wrong? If so, what did they do wrong?

Multiple Choice

Problem 2:

$$3\ \frac{3}{4}\ •\ \ 2\ \ =\ 6\ \frac{3}{4}$$

What is the correct answer?

• 7 1/2
• 7 3/4
• 6 1/4
• 5 1/2

Open Ended

Problem 3:

$$1\ \frac{1}{4}\ •\ \ 2\ \frac{2}{3}\ =\ 3\ \frac{1}{3}$$

Is this answer wrong? If so, what did they do wrong?

Multiple Choice

Problem 3:

$$1\ \frac{1}{4}\ •\ \ 2\ \frac{2}{3}\ =\ 3\ \frac{1}{3}$$

What is the correct answer?

• 2 1/2
• 4 1/4
• 3 2/3
• 3 1/3

Open Ended

Problem 4:

$$2\ \frac{5}{6}\ •\ \ 1\ \frac{1}{2}\ =\ 4\ \frac{3}{12}$$

Is this answer wrong? If so, what did they do wrong?

Multiple Choice

Problem 4:

$$2\ \frac{5}{6}\ •\ \ 1\ \frac{1}{2}\ =\ 4\ \frac{3}{12}$$

What is the correct answer?

• 3 1/4
• 4 3/12
• 5 2/3
• 2 1/2

Open Ended

Problem 5:

$$4\ \frac{1}{2}\ •\ \ 1\ \frac{1}{4}\ =\ 4\ \frac{1}{8}$$

Is this answer wrong? If so, what did they do wrong?

Multiple Choice

Problem 5:

$$4\ \frac{1}{2}\ •\ \ 1\ \frac{1}{4}\ =\ 4\ \frac{1}{8}$$

What is the correct answer?

• 5 5/8
• 6 1/2
• 5 1/4
• 4 3/4

Open Ended

Problem 6:

$$3\ \frac{2}{5}\ •\ \ 2\ \frac{1}{2}\ =\ 8\ \frac{1}{2}$$

Is this answer wrong? If so, what did they do wrong?

Multiple Choice

Problem 6:

$$3\ \frac{2}{5}\ •\ \ 2\ \frac{1}{2}\ =\ 8\ \frac{1}{2}$$

What is the correct answer?

• 8 1/2
• 6 2/5
• 9 1/4
• 7 3/4

Open Ended

Problem 7:

$$1\ \frac{3}{4}\ •\ \ 1\ \frac{1}{3}\ =\ 2\ \frac{4}{12}$$

Is this answer wrong? If so, what did they do wrong?

Multiple Choice

Problem 7:

$$1\ \frac{3}{4}\ •\ \ 1\ \frac{1}{3}\ =\ 2\ \frac{4}{12}$$

What is the correct answer?

• 2 1/3
• 3 1/2
• 1 3/4
• 2 1/4

Open Ended

Problem 8:

$$2\ \frac{1}{2}\ •\ \ 1\ \frac{2}{3}\ =\ 4\ \frac{1}{6}$$

Is this answer wrong? If so, what did they do wrong?

Multiple Choice

Problem 8:

$$2\ \frac{1}{2}\ •\ \ 1\ \frac{2}{3}\ =\ 4\ \frac{1}{6}$$

What is the correct answer?

• 4 1/6
• 5 1/2
• 3 3/4
• 2 2/3

Open Ended

Problem 9:

$$3\ \frac{1}{6}\ •\ \ 2\ \frac{1}{2}\ =\ 7\ \frac{11}{12}$$

Is this answer wrong? If so, what did they do wrong?

Multiple Choice

Problem 9:

$$3\ \frac{1}{6}\ •\ \ 2\ \frac{1}{2}\ =\ 7\ \frac{11}{12}$$

What is the correct answer?

• 6 5/12
• 8 1/4
• 7 11/12
• 7 1/2

Open Ended

Problem 10:

$$1\ \frac{5}{8}\ •\ \ 2\ \ =\ 2\ \frac{5}{8}$$

Is this answer wrong? If so, what did they do wrong?

Multiple Choice

Problem 10:

$$1\ \frac{5}{8}\ •\ \ 2\ \ =\ 2\ \frac{5}{8}$$

What is the correct answer?

• 3 3/8
• 2 1/2
• 3 1/4
• 1 7/8

Open Ended

Problem 11:

$$2\ \frac{2}{3}\ •\ \ 3\ \frac{1}{2}\ \ =\ 9\ \frac{2}{6}$$

Is this answer wrong? If so, what did they do wrong?

Multiple Choice

Problem 11:

$$2\ \frac{2}{3}\ •\ \ 3\ \frac{1}{2}\ \ =\ 9\ \frac{2}{6}$$

What is the correct answer?

• 8 2/3
• 10 1/4
• 7 3/5
• 9 1/3

Open Ended

Problem 12:

$$4\ \frac{3}{4}\ •\ \ 1\ \frac{1}{5}\ \ =\ 5\ \frac{14}{20}$$

Is this answer wrong? If so, what did they do wrong?

Multiple Choice

Problem 12:

$$4\ \frac{3}{4}\ •\ \ 1\ \frac{1}{5}\ \ =\ 5\ \frac{14}{20}$$

What is the correct answer?

• 5 14/20
• 4 3/5
• 5 1/4
• 6 2/10