Stage 8 · Fractions & decimals
Adding like fractions
Same bottom: add the tops, then simplify.
How to do it
Method
Same bottom: add the tops, then simplify
38 + 18 = 48 = 12
One more example
1 − 38 = 88 − 38 = 58
In full
The same denominator means pieces of the same size: keep the denominator and add or subtract the numerators. 38 + 18 → 3 + 1 = 4 → 48. Give the answer in simplest form: divide the top and bottom by their highest common factor, 48 → 12. To take a fraction from 1, write 1 over the same denominator first: 1 − 38 = 88 − 38 = 58.
Worked examples
Have a go first, then open each one for the answer and the working.
Example 1
611 + 111
Answer in simplest form
Show the answer and working
Answer: 611 + 111 = 711
611 + 111: keep the denominator, add the numerators, 6 + 1 = 7 → 711, already in simplest form
Example 2
811 + 211
Answer in simplest form
Show the answer and working
Answer: 811 + 211 = 1011
811 + 211: keep the denominator, add the numerators, 8 + 2 = 10 → 1011, already in simplest form
Example 3
19 + 29
Answer in simplest form
Show the answer and working
Answer: 19 + 29 = 13
19 + 29: keep the denominator, add the numerators, 1 + 2 = 3 → 39; simplify, dividing top and bottom by their highest common factor 3: 3 ÷ 3 = 1, 9 ÷ 3 = 3 → 13
Example 4
112 + 112
Answer in simplest form
Show the answer and working
Answer: 112 + 112 = 16
112 + 112: keep the denominator, add the numerators, 1 + 1 = 2 → 212; simplify, dividing top and bottom by their highest common factor 2: 2 ÷ 2 = 1, 12 ÷ 2 = 6 → 16
Practise adding like fractions in the game →Stage 8 · Fractions & decimals · Free to start, unlimited questions, no download