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How to add and subtract fractions

Example 1 - Adding and subtracting with fractions

Work out 3/4+1/6

Before we can add any fractions we must convert to a common denominator first.

This is found by finding the first common multiple of 4 and 6 which is 12.

If you don't find the first common multiple but

instead use 24 or 36 etc you will still get to the same answer but have

to do harder calculations along the way!

Now we have to convert both fractions to the

common denominator of 12 by multiplying the numerators and denominators

of both fractions by 3 and 2 respectively:

3×34×3=912 and 1×26×2=212.

Now the fractions have the same denominator we simply add the numerators together to get:

9/12+2/12=11/12

How to add and subtract mixed numbers

Example 2 - Adding and subtracting with mixed numbers

Work out 2/35+3/12

When adding mixed numbers you can make life

easier for yourself my first adding the whole numbers together. In this

case 2 + 3 = 5.

Now we just have to work out the remaining

fraction sum 35+12.

The common denominator of 35+12 is 10. So we multiply the numerators and denominators of both fractions by 2 and 5 respectively.

3×25×2=610 and 1×52×5=510. Adding these together gives us 1110.

Finally, remember to add on the 5 from the beginning of the questions to get 51110=6110.