When fractions have the same denominator, the parts are the same size. So add or subtract the numerators and keep the denominator: 3/8 + 4/8 = 7/8 and 7/10 − 2/10 = 5/10.
Never add the denominators. 1/4 + 1/4 is 2/4, which is a half, not 2/8. If the answer can be simplified, simplify it: 5/10 = 1/2. If the numerator becomes bigger than the denominator, the answer is more than one whole.
Worked example
5/12 + 4/12 =
- Same denominator, so add the numerators: 5 + 4 = 9.
- 9/12 simplifies by dividing by 3.
Answer:9/12 = 3/4
Key words
- like fractions
- fractions with the same denominator
- simplify
- write in simplest form
- improper fraction
- numerator bigger than the denominator
Practise this
New questions every time.
Common Core-referenced: 4.NF.B.3a