 ## 50 Common Mistakes to Avoid in Math

How many times have you seen the same types of common mistakes occurring in your child’s Math papers?

How many marks can your child save if he can avoid those common mistakes?

Instead of letting your child make all those mistakes and losing precious marks in the exams, why not expose your child to these mistakes and teach your child to avoid them?  Learning from Others’ Mistakes

Most centres or tutors will make their students do corrections and learn from their own mistakes.

We invert the whole teaching process by telling your child the mistakes made by others and how to avoid them.

This process will shorten your child’s learning journey so that your child can see improvements and results in a shorter time.

All our Math tutors have been in this field long enough to know exactly what the common mistakes are.

Without further ado, here are 50 common mistakes to avoid in Math….

## Whole Numbers Common Mistakes

1. Subtract A from B
Wrong: A – B
Correct: B – A

2. Incorrect Workings
Wrong
30 – 2 × 6
= 12 (Marks will be deducted for wrong workings though the answer is correct)
= 30 – 12
= 18

Correct
30 – 2 × 6
= 30 – 12
= 18

3. Order of Operations
Wrong
50 – 3 × 2
= 47 × 2
= 94

Correct
50 – 3 × 2
= 50 – 6
= 44

4. Values with Different Units
5 kg worth of flour is packed into bags of 100g. How many bags are there?
Wrong
5 ÷ 100 = 0.05
Correct
5 kg = 5000 g
5000 ÷ 100 = 50

5. Cut into Pieces
Tom takes 8 minutes to cut a block of wood into 5 pieces. How long will he take to cut it into 10 pieces?
Wrong
8 ÷ 5 × 10 = 16 min
Correct
5 pieces → 4 cuts, 10 pieces → 9 cuts
8 ÷ 4 × 9 = 18 min

6. Gaps / Intervals
Some pots were placed at equal intervals apart. If the first and the 15th pot were 42 m apart, how far apart were the first and the 10th?

Wrong
42 ÷ 15 × 10 = 28
Correct
15 pots → 14 gaps
10 pots → 9 gaps
42 ÷ 14 × 9 = 27

7. Group of Items
3 pens were sold for \$20. How much do 18 pens cost?
Wrong
18 × \$20 = \$360
Correct
18 ÷ 3 = 6
6 × \$20 = \$120

8. Places
Write 70 tenths as a decimal.
Wrong: 0.70
Correct: 7.0

## Fractions Common Mistakes

9. Fraction of
Express \$2 as a fraction of 80 cents.
Wrong: 80200 = 25
Correct: 20080 = 52

10. Fraction with Units
May had 89 m of ribbon. She used 12 m of it. How much does she have left?
Wrong: 89 × 12 = 49
Correct: 8912 = 718

11. Remainder with Fraction
There was 89 of a pizza. Each person ate 13 of a pizza. What fraction of a pizza was left?

Wrong
89 ÷ 13
= 89 × 3
= 83
= 223
Remainder = 23 (There is a missing step!)
Correct
23 × 13 = 29

12. Fraction of Total
John spends 13 of his money on A and 15 of his money on B. What fraction of his money does he have left?

Wrong: 45 × 23 = 815
Correct: 1 – 1315 = 715

13. Fraction of Remainder
John spends 13 of his money on A and 15 of the remaining money on B. What fraction of his money does he have left?

Wrong: 1 – 1315 = 715
Correct: 45 × 23 = 815

14. Splitting Fractions
How many 16 are there in 316?

Wrong: 3 + 1 = 4
Correct: 3 × 6 + 1 = 19

15. Rest of Fraction
25 of the apples are red, the rest are green.
Wrong: Red → 2u, Green → 5u
Correct: Red → 2u, Green → 3u, Total → 5u

16. Equal Fractions
13 of A is equal to 25 of B.
Wrong
13A = 25B
515A = 615B (Do not make denominator the same!)

Correct
13A = 25B
26A = 25B (Make numerator the same)

17. Equal Fractions (Multiple)
15 of A is twice of 310 of B.

Wrong
15A = 310B
315A = 310B

Correct
15A = 310B
630A = 310B (Make numerator of A twice of the numerator of B)

18. Compare Fractions of Same Denominator
Arrange 13, 15 and 110 in ascending order

Wrong: 13, 15 and 110
Correct: The bigger the denominator, the smaller the fraction
110, 15 and 13

19. Branching
Josh gave 12 his stickers to his brother and 5 to his sister.
Wrong Correct
Fractions should add up to 1
Signs should be opposite
Numbers should be the same   ### Follow Jimmy Maths on Telegram here!

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