# ISEE Middle Level Math : How to add fractions

## Example Questions

### Example Question #71 : How To Add Fractions

Explanation:

When adding fractions, we must find a common denominator.  So, given the fractions

we see the denominators are 2 and 4.  The common denominator of 2 and 4 is 4.  So, we must make both denominators equal 4.  So,

How can we write  as a fraction with 4 in the denominator?  We must determine what number we can multiply the denominator by to get 4.  Once we determine that, we multiply the numerator by the same number.  So,

So 2 times what number will give us 4?  The answer is 2.  So,

Now that we know that, we must multiply the numerator by the same number.  So,

and we get

Now, the 2 fractions have the same denominator, so we can add them.  So,

When we add fractions, we add only the numerator and the denominator stays the same.  So,

### Example Question #72 : How To Add Fractions

Solve the following:

Explanation:

To subtract fractions, we need to find a common denominator, then we subtract the numerators only.

So, given the problem

we can see we already have a common denominator. So, we will now subtract the numerators (note that we will leave the denominator alone). We get

### Example Question #73 : How To Add Fractions

Explanation:

To add fractions, we need to have a common denominator.  Then, we will add only the numerators, and we will leave the denominators alone.

So, given the problem

we will find a common denominator. To do that, we will find the least common multiply.

We can see the least common multiply is 6. So, the denominator will be 6.

If we change the denominators to 6, we have to adjust the numerators accordingly. So, we get

Now, we can add. We get

### Example Question #74 : How To Add Fractions

Solve the following

Explanation:

To add fractions, we first add the numerators, and the denominator stays the same because it is the whole.

.

This gives us

.

This is equal to  which is reduced to

Solve: