1. Percentages
What are Percentages?

2. Percentages are measures out of a 100

3. This grid is made up of 100 squares
This grid is made up of 100 squares. We will use it to look at percentages.

4. In this case, fifty percent is shaded
We write this as 50%

5. The following grids also show 50%.

6. These grids show 25%

7. And these show 10%

8. Can you name these percentages?
40%
70% ? ? 5%
64%

9. Finding Simple Percentages of Numbers

10. Finding Fifty Percent (50%)
50% is the easiest percentage to find.
All you have to do is halve your number.

11. Here is an example
Find 50% of 70
70 ¸ 2 = 35

12. Why do you divide by 2?
The reason you divide by two is because there are two fifties in one hundred.
100 ¸ 50 = 2

13. Find 50% of the following numbers.40 18
50% of 40 = 20
50% of 18 = 9
130 15
50% of 130 = 65
50% of 15 =
7.5

14. Finding Ten Percent (10%)
10% is an easy percentage to find.
All you have to do is divide your number by ten.

15. Here is an example
Find 10% of 40
40 ¸ 10 = 4

16. Why do you divide by 10?
The reason you divide by ten is because there are ten tens in one hundred.
100 ¸ 10 = 10

17. Find 10% of the following numbers.60
150
10% of 60 = 6
10% of 150 = 15
240 45
10% of 240 = 24
10% of 45 =
4.5

18. Finding One Percent 1% is a little bit more difficult to find.
To work out 1% you divide your number by one hundred.

19. Missing Pages

20. Calculating Percentages without a Calculator.

21. Finding various percentages of 160.

22. Calculate 50% of 160
160
50% of 160 = 80

23. 25% is half of 50%
160
50% of 160 = 80 40
25% =

24. 75% is 50% + 25%
160
50% of 160 = 80
25% = 40
75% =
120

25. 10% is 160 ¸ 10
160
50% of 160 = 80
25% = 40
75% =
120 16
10% =

26. Missing Pages

27. and 9% is 9 x 1% 160 50% of 160 = 80 25% = 40 75% = 120 10% = 16 40% =64
20% = 32
1% =
1.6
2% =
3.2
9% =
14.4

28. Challenge
Find 63% of 250.

29. Start with 250
250

30. Calculate 50% of 250
250
50% of 250 =
125

31. Calculate 10% of 250
250
50% of 250 =
125 25
10% =

32. 60% = 50% + 10%
250
50% of 250 =
125
10% = 25 +
150
60% =

33. Missing Pages

34. 63% is 60% + 3%
250
50% of 250 =
125
10% = 25
60% =
150 +
1% =
2.5
3% =
7.5
157.5
63% =

35. Calculating Percentages with a Calculator.

36. Percentages
The general method used here is to find 1%, then calculate the percentage you are looking for.
For example, to find 21% of a number, you would divide it by 100, then multiply by 21.

37. Calculating 21% of 80
Use your calculator to find the answer to this problem.
80 ¸ 100 x 21 = ?

38. Calculating 21% of 80
Use your calculator to find the answer to this problem.
80 ¸ 100 x 21 =
16.8

39. Calculating 83% of 155
Use your calculator to find the answer to this problem.
155 ¸ 100 x 83 = ?

40. Calculating 83% of 155
Use your calculator to find the answer to this problem.
155 ¸ 100 x 83 =
128.65

41. Try these… 1. 18% of 60 2. 32% of 82 77% of 144 99% of 150 52% of 52
= 10.8
= 26.24 =
= 148.5 =
= 24
= 36.08

42. Percentages ORB Education By S. Howarth
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