Question

Pedro simplified four over seven divided by five over eight.; his work is shown below. Identify where he made his error.

Original division problem: four over seven divided by five over eight.

Step 1: four over seven multiplied by eight over five.

Step 2: four times five over seven times eight.

Step 3: twenty over fifty-six.

Step 4: five over fourteen.

Answer 1

Solve the problem yourself first, to see if Pedro made any mistakes.

4/7 x 8/5

4x8 = 32

7x5 = 35

32/35 is the answer.

Pedro made his error in step 2, he cross multiplied instead of multiplying the numerators, and then the denominators.

Answer 2

The error is from Step 1 to Step 2. You don't cross multiply when the two fractions are multiplied.