You just have to multiply straight across. Multiply the numerators for the new numerator, and the denominators for the new denominator.
5*3=15
4*8=32
15/32 is the answer (b).
The commutatice property for addition says a+b=b+a
If it was for subtraction, then it would be a-b=b-a
Take a=7 and b=5
7-5 is not equal to 5-7
2 is not equal to -2
So subtraction is not commutative for whole numbers.
Hope this helps :)
49
Because 7x7 is 49 & 4+9=13