Question

Question #6913e

Answer 1

1) The simplest one to explain is multiplication. When multiplying fractions you just multiply the tops and the bottoms, like this:

`A/B xx C/D= (A xx B)/(C xx D)`

2) Division of fractions is a multiplication by the inverse of the dividing fraction, like this:

`(A/B)/(C/D)= A/B xx D/C`

3) Addition and subtraction involve finding a common multiple of the denominators (the bottom parts), so you can then add or subtract the top parts (numerators). The easiest way is to multiply one denominator by the other and then multiply the numerators by the opposite denominator, like this:

`A/B + C/D = (AxxD)/(BxxD) +(CxxB)/(BxxD)`

Now, since both denominators are the same (`BxxD`) we can just write the numerators together under a single denominator:

`(AxxD+CxxB)/(BxxD)`

This works exactly the same for subtraction.