[alternap18]

how do you do it?

do you go left of the bottom straight and then cross multiply?

what are the steps like here's an example 3/4 + 7/8
do you do 4x8 then 4x7 then 3x8 then 3x7?

[ebaines]

When adding fractions with different denominators the first step is to convert one or both of the fractions so that they have the same denominator. An easy way to do that is to multiply the numerator and denominator of each fraction by the amount of the other fraction's denominator. For example: consider 3/4 + 7/9. You can multiply 3/4 x 9/9 to get 27/36. And you can multiply 7/9 by 4/4 to get 28/36. Note in both cases you are multiplying by the equivalent of 1, so this doesn't change the value of the fraction. Now you can easily add the two fractions:

3/4 + 7/9 = 3/4 x 9/9 + 7/9 x 4/4 = 27/36 + 28/36 = 55/36.

For the example you cited you can follow this same technique:

3/4 + 7/8 = 3/4 x 8/8 + 7/8 x 4/4 = 24/32 + 28/32 = 52/32, which simplifies to 13/8.

However, in this case it can be solved a bit simpler if you notice that one denominator is a multiple of the other. Here the 8 is two times 4, so you really only need to multiply the fraction 3/4 by 2/2, like this:

3/4 + 7/8 = 3/4 x 2/2 + 7/8 = 6/8 + 7/8 = 13/8.

Hope this helps!

[Just Looking]

Deleted

[Just Looking]

Answer deleted - Ebaines beat me to it.

[alternap18]

um you know I already know if they're the same on the bottom you can add them on the top
like this
1/8+1/8=2/8
that's easy
but how many steps are they're?

[ebaines]

um you know i already know if theyre the same on the bottom you can add them on the top
like this
1/8+1/8=2/8
thats easy

Right - that's why the objective in adding fractions is to get the denominators (the "bottoms" as you say) to be the same.

but how many steps are theyre?

Sorry? I don't understand the question - could you please restate this?

[alternap18]

for adding fractions
how many steps are they're

3 6
- + -
5 4 ------ 5x4

do you multiply across 1st?

[ebaines]

Given: 3/5 + 6/4

Step 1. Multiply the first fraction by 4/4: 3/5 x 4/4 = 12/20

Step 2. Multiply the 2nd fraction by 5/5: 6/4 x 5/5 = 30/20

Step 3: Add: 12/20 + 30/20 = 42/20

Step 4: Simplify: 42/20 = 21/10.

So that seems to be 4 steps.