The 2-digit number chosen to divide by 3 1/2 is 42.

Multiply by 2: 2 × 42 = 84

Divide by 7: 84/7 = 12

So 42 divided by 3 1/2 = 12.

See the pattern?

The 2-digit number chosen to divide by 3 1/2 is 61.

Multiply by 2: 2 × 61 = 122

Divide by 7: 122/7 = 17 3/7

So 61 divided by 3 1/2 = 17 3/7.

If the number chosen is divisible by 7, the answer will be
a whole number. For numbers not divisible by 7, a calculator will get
a repeating decimal, but your fractional answer will be exact.