RemeliaMaths Year 4 Fractions, decimals & %
Year 4 fractions: six questions and the common mistakes
Under each answer are the wrong answers a child often gives to it, seven different mistakes on this page, and what Remelia tells the child who gives one.
Questions written by Remelia for the objectives of the national curriculum for England; not taken from any test paper.
Six questions
-
What fraction of the shape is shaded?
Write it as a fraction with a denominator of 20.
- A 16/20
- B 17/20
- C 15/20
- D 3/20
Show the answer to question 1
Answer: C · 15/20
Why:
3 of the 4 equal squares are shaded: 3/4.
20 ÷ 4 = 5, so each part is 5/20. 3 × 5 = 15.
So 3/4 = 15/20.
Common mistakes:
- 3/1: It looks as if you put the parts not shaded as the denominator. The denominator is how many equal parts there are altogether; the numerator is how many are shaded.
- 5/20: That is the fraction not shaded. The numerator counts the shaded parts.
-
Elif has 80 buttons and gives away 2/8 of them.
How many are left?
Show the answer to question 2
Answer: 60
Why:
2/8 of 80 = 20. Left: 80 − 20 = 60. (Or: 6/8 of 80 = 60.)
Common mistakes:
- 20: That is the part given away. The question asks how many are left, so take it away from the whole.
-
8/11 + 1/11 = ?
Write your answer as a fraction.
- A 9/11
- B 7/11
- C 8/11
- D 6/11
Show the answer to question 3
Answer: A · 9/11
Why:
Same denominator, so just add the numerators: 8 + 1 = 9.
Answer: 9/11. The denominator stays 11.
Common mistakes:
- 9/22: It looks as if you added the denominators too. When the denominators are the same, add only the numerators. The denominator stays the same.
-
Write 29 hundredths as a decimal.
Show the answer to question 4
Answer: 0.29 (also accept .29)
Why:
100 hundredths make one whole, so 29 hundredths = 29 ÷ 100 = 0.29.
The last digit of 29 goes in the hundredths column, the second place after the point.
Common mistakes:
- 2.9: Your digits are right, but in the wrong columns: your answer is 10 times too big.
-
Write 1/10 as a decimal.
Show the answer to question 5
Answer: 0.1 (also accept .1)
Why:
1/10 = 0.1. These are worth learning by heart. They come up constantly.
Common mistakes:
- 1.10: It looks as if you wrote the numerator, a point, then the denominator. A fraction is a division: the numerator divided by the denominator. A fraction less than one whole is a decimal less than 1.
-
In 93.15, which digit is in the ones place?
Show the answer to question 6
Answer: 3
Why:
93.15: 9 tens, 3 ones, 1 tenth, 5 hundredths.
Common mistakes:
- 9: That digit is in a different column. After the decimal point come tenths, then hundredths, then thousandths.
Answers
- 1. C · 15/20
- 2. 60
- 3. A · 9/11
- 4. 0.29 (also accept .29)
- 5. 0.1 (also accept .1)
- 6. 3
How Remelia uses a mistake
When a wrong answer matches one of these mistakes, the app says what the child seems to have done before they try again, and brings the objective back on a later day.
Remelia practises maths for the child's own year group, in short sessions, and brings back on later days what they got wrong.