Use the bbc website to help you add fractions.
Remember the denominators must be the same to add together.
i.e. 1/2 + 1 /4 turn the 1/2 into 4ths by multiplying by 2 and what you do to the denominator you do to the numerator so you end up with 2/4. Now you can add 2/4 to 1/4 = 3/4