RemeliaMaths Year 4 Fractions, decimals & %
Year 4 adding and subtracting fractions
The objective: Add and subtract fractions with the same denominator.
The explanation, example and questions are the ones Remelia uses in the app; the questions are not taken from any test paper.
The idea
Same denominator means same-sized pieces, so you simply count the pieces. Add the tops, keep the bottom.
How to do it
- Check the denominators match.
- Add or subtract the numerators only.
- If the answer is more than a whole, you can convert it: 7/5 is 1 and 2/5.
A worked example
5/8 − 2/8 = 3/8.
Watch for
Adding the denominators. 2/9 + 4/9 = 6/9, never 6/18.
Try four questions
-
8/11 − 2/11 = ?
Write your answer as a fraction.
Show the answer to question 1
Answer: 6/11 · accept equivalent fractions
Why:
Same denominator, so just subtract the numerators: 8 − 2 = 6.
Answer: 6/11. The denominator stays 11.
-
5/7 + 2/7 = ?
Write your answer as a fraction.
- A 10/7
- B 8/7
- C 7/7
- D 9/7
Show the answer to question 2
Answer: C · 7/7
Why:
Same denominator, so just add the numerators: 5 + 2 = 7.
Answer: 7/7. The denominator stays 7.
-
A garden is split into 5 equal beds.
Priya plants 2/5 of it and Theo plants 1/5 of it.
What fraction is left? Write your answer as a fraction.
Show the answer to question 3
Answer: 2/5 · accept equivalent fractions
Why:
Together they plant 2/5 + 1/5 = 3/5.
The whole is 5/5, so 5/5 − 3/5 = 2/5 is left.
-
6/12 + 1/12 = ?
Write your answer as a fraction.
Show the answer to question 4
Answer: 7/12 · accept equivalent fractions
Why:
Same denominator, so just add the numerators: 6 + 1 = 7.
Answer: 7/12. The denominator stays 12.
Answers
- 1. 6/11 · accept equivalent fractions
- 2. C · 7/7
- 3. 2/5 · accept equivalent fractions
- 4. 7/12 · accept equivalent fractions
The mistakes Remelia names
When a wrong answer to a question like these matches one of these mistakes, the app says what the child seems to have done before they try again.
- Question 1, the answer 6/0: It looks as if you took away the denominators too. When the denominators are the same, subtract only the numerators. The denominator stays the same.
- Question 2, the answer 7/14: It looks as if you added the denominators too. When the denominators are the same, add only the numerators. The denominator stays the same.
- Question 3, the answer 3/5: That is the part given away. The question asks how many are left, so take it away from the whole.