Step by step
The question
Question: add 1/2x + 1/3x.
1 Find the common bottom
The bottoms are 2x and 3x.
The common bottom must have every factor of both bottoms, each one once.
For the numbers: 6 is the smallest number both 2 and 3 go into.
It is 6x.
Careful!
We can't add the tops and add the bottoms.
Fractions need the same bottom first.
2 Make the bottoms the same
The first fraction is missing 3.
We multiply its top and bottom by 3.
The second fraction is missing 2.
We multiply its top and bottom by 2.
3/3 is 1, so the value stays the same.
3 Add the tops
Now one fraction: (1 × 3 + 1 × 2)/6x.
On top: 1 × 3 + 1 × 2 is 5.
So the top is 5.
4 Cross out the same
Is a whole factor on top the same as one on the bottom?
No.
So nothing crosses out.
We leave the bottom as factors.
So the answer is 5/6x.
The bottoms can't be 0.
So x can't be 0.
5 Check
Let's check with a number: x = 1.
First in the question.
1/2 plus 1/3 is 5/6.
Now in our answer.
We get 5/6 too.
Both are 5/6.
So 5/6x is right!
Let's look back.
First: find the common bottom.
Then: make the bottoms the same.
Then: add the tops.
Then: cross out the same.
Last: check.