How would you multiply 11/15 and 12/17?

'horizontal multiplication' is required when multiplying fractions.

So the sum is essentially this: 11x12 / 15x17

11x12: mutliply 12 by 10 (so add a zero at the end); add 12 x 1(so 12) to that number; the answer is 132

15x17: if you are familiar with square numbers you'll know 15 x 15 is 225; 15 x 2 is 30; add these two; the answer is 255

answer = 132/255

If the question asks for simplification:

start with the smallest number, so 132.

Ask: can this be divided by 2? yes.

Then: can 255 be divided by 2? no (it ends in 5)

move through consecutive numbers

answer = 44/85

both can be divided by 3

Multiply the numerators for both fractions divided by the product of the two denominations for the final answer.