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Percentages

Percentages. What are Percentages?. Percentages are measures out of a 100. Percentages. This grid is made up of 100 squares. We will use it to look at percentages. In this case, fifty percent is shaded. We write this as 50%. The following grids also show 50%. These grids show 25%.

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Percentages

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  1. Percentages What are Percentages?

  2. Percentages are measures out of a 100 Percentages

  3. 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. Percentages 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. Find 50% of 70 Here is an example 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. Find 10% of 40 Here is an example 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. Percentages Calculating Percentages without a Calculator.

  21. 160 Finding various percentages of 160.

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

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

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

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

  26. Missing Pages

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

  28. Challenge Find 63% of 250.

  29. 250 Start with 250

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

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

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

  33. Missing Pages

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

  35. Percentages 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 • 1.5% of 16 • 41.7% of 88 = 10.8 = 26.24 = 110.88 = 148.5 = 527.04 = 24 = 36.08

  42. Percentages By S. Howarth • ORB Education Visit http://www.orbeducation.com for a range of quality teaching materials.

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