Mental Maths
Percentage of Amount
Percentage Increase
Percentage Decrease
Estimation
100

22 + 57 =

79

100

Find 50% of 40

What is 20

100

Increase 100 by 50%

What is 150

100

Decrease 100 by 10%

What is 90

100

97x5

What is the best estimate of this multiplication

500

200

37 + 44 =

81

200

Find 10% of 65

What is 6.5

200

Increase 70 by 50%

What is 105

200

Decrease 60 by 50%

What is 30

200

32 x 12

What is the best estimate of this multiplication

300

300

74-25

49


300

Find 5% of 80

What is 4

300

Increase 40 by 25%

What is 50

300

Decrease 50 by 10%

what is 45

300

48 x 2.8

What is the best estimate of this multiplication

150

400

152 - 126 =

26

400

Find 75% of 60

What is 45

400

Increase 540 by 10%

What is 594

400

Decrease 20 by 20%

What is 16

400

83 divided by 4

What is the best estimate of this division

20

500

86 - 32 =

53

500

Find 90% of 70

What is 63

500

Increase 80 by 5%

What is 84

500

Decrease 78 by 10%

What is 70.2

500

8.7 divided by 2.8

What is the best estimate of this division

3