BIDMAS

a) Twenty-thousand four hundred

b) -21

A + * by a – is always a –

c) 27

BIDMAS. Brackets first

d) 8

y=16/2 = 8

e)i) x = 7

e)ii) x = 5

You firstly have -x = -5 which is the same as x = 5

f) 6

g) 1:3

a) 4

BIDMAS. Do multiplication first. So 16-12 = 4

b) 70%

When converting decimals to percentages, just move the decimal place 2 places to the right. So 0.7 becomes 70.

c) 0.6

3/5ths as a decimal. To convert denominator to 100, multiply both numerator and denom by 20. So 60/100 = 0.6

d) 18

15/100 * 120/1

e) 20 – 10 /5 = 18

Do division first according to BIDMAS. Then subtraction. So 20-2 = 18

f) 16+(32/8/2)-1 = 16 + 2 – 1  = 17

A

120

1. Use BIDMAS
2. 20 + (1 x 7) = 27
3. (20 + 1) x 7 = 147
4. 147-27

74

1. (4+2) x 13 = 104
2. 4 + (2×13) = 30
3. Difference = 104 – 30

70

1. Use BIDMAS. (7+3) x 11 = 10 x 11 = 110
2. 7+ (3×11) = 40
3. 110-40 = 70

Work backwards for this section….

Use BIDMAS

a) 5

b) 26

c) 112

Apply the rules of BIDMAS. Brackets, Indices, Division, Multiplication, Addition, Subtraction

D

1. Use BIDMAS. Therefore…
2. 32-8
3. 24

E

1. Apply the rules of BIDMAS
2. 12-8+3
3. 12-11
4. 1

5

1. Use BIDMAS. So Brackets, Indices, Division, Multiplication, Addition & Subtraction
2. In that order
3. First we do Multiplication. So 5 x 2 = 10
4. Revised question becomes 21-10+6
5. Then addition so 21-16
6. Then subtraction
7. So answer is 5

See below

Ensure BIDMAS rules are applied

b)

Remember the question is asking for the incorrect answer. In this case its b)

a) 38

BIDMAS. Do the multiplication first. 7×9 = 63. So, 63 – ? =25. Rearrange. -?=25-63. -?=-38.

b) 9

64/4 = 16. 16= ?+7

c) 10

36 = 16 + (2 x?). Rearrange. 36-16 = 2x?.  20/2 = ?

You can always substitute the numbers back into the equations to ensure your answer is correct

a) 11

Work out RHS first = 26. Then rearrange formula if needed. ? = 26 – 15. Therefore ? =11

b) 5

2+20 = 27 – ?

BIDMAS

c) 0.5

18/3 = 6. ?  x 12 = 6. This would bee 0.5

a) 19

(5 x 4) -1

b) 8

Remember that normally, it would be takeaway 6 on the left hand side. If you take this to the other side, it will become addition. So lets do this:

m ? = 26 + 6

m ? = 32. So given its ? x 4, ? must be 8

c) 7

5 ? (4 * 4 – 3)

5 ? – (13) = 5 * 4 – (13) = 20 – 13 = 7

d) 9

[(6 X 4) – p ] x 4 = 56

[24 – p] x 4 – 4= 56

96 -4p-4 = 56

-4p=56-96+4

-4p = -36

p=9

a) 2

Solve what you can. So 23 x ? = 46. Then re-arrange the formula. ? = 46/23 = 2

b) 4

Remember BIDMAS. Solve 5-2 first = 3. So 3 to power of 2 is 3×3 = 9.

13 = ? + 9. Re-arrange to give 4

c) 9

2 + 6 = 8

72 ÷ ? = 8. Re-arrange to give 9