1.4.4

Test yourself

When we add or subtract fractions, we must make sure the denominator of both fractions is the same.

### Same denominator

• If the denominator of both fractions is already the same we simply add or subtract the numerators.

### Same denominator 2

• If the denominator of both fractions is already the same we simply add or subtract the numerators.

### Different denominators

• If the denominators are not the same we need to make them the same using an equivalent fraction.

### Different denominators 2

• When finding an equivalent fraction we must multiply or divide both the top and bottom row by the same amount.

### Different denominators 3

• Once both the fractions have the same denominator we can add or subtract the numerators.

### What is $\frac{3}{4} - \frac{1}{5}$?

• We cannot do the subtraction straight away because the fractions do not have the same denominator.

### What is $\frac{3}{4} - \frac{1}{5}$?

• Using equivalent fractions, convert the fraction so that they have the same denominator.

### What is $\frac{3}{4} - \frac{1}{5}$?

• Once both the fractions have the same denominator we can add or subtract the numerators.