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Published byDwight Hilary O’Connor’ Modified over 8 years ago

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Percentages What are Percentages?

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Percentages are measures out of a 100 Percentages

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

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

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The following grids also show 50%.

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These grids show 25%

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And these show 10%

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

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Finding Simple Percentages of Numbers Percentages

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

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Here is an example Find 50% of 70 70 35

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

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

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

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Here is an example Find 10% of 40 40 4

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

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

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

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Here is an example Find 1% of 120 120 1.2

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Why do you divide by 100? The reason you divide by one hundred is because there are one hundred ones in one hundred. 100 100 = 1

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Find 1% of the following numbers. 200 1% of 200 =2 1500 1% of 1500 =15 50 1% of 50 = 0.5 25 1% of 25 =0.25

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Calculating Percentages without a Calculator. Percentages

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160 Finding various percentages of 160.

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160 Calculate 50% of 160 50% of 160 80

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160 50% of 160 80 25% is half of 50% 25% 40

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160 50% of 160 80 25% 40 75% is 50% + 25% 75% 120

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

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160 50% of 160 80 25% 40 75% 120 10% 16 20% is double 10% 20%

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160 50% of 160 80 25% 40 75% 120 10% 16 20% and 40% is double 20% 40% 64

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160 50% of 160 80 25% 40 75% 120 10% 16 20% 40% 64 1% is 160 100 1%

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160 50% of 160 80 25% 40 75% 120 10% 16 20% 40% 64 1% 2% is double 1% 2% 3.2

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

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

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Challenge Find 63% of 250.

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250 Start with 250

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250 50% of 250 125 Calculate 50% of 250

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Calculate 10% of 250 250 50% of 250 125 10% 25

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

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Calculate 1% of 250 250 50% of 250 125 10% 25 60% 150 + 1% 2.5

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3% is 3 x 1% 250 50% of 250 125 10% 25 60% 150 + 1% 2.5 3% 7.5

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

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and 9% is 9 x 1% 250 50% of 250 125 10% 25 1% 2.5 60% 150 3% 7.5 63% 157.5 +

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Calculating Percentages with a Calculator. Percentages

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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.

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

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

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

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

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Try these… 1. 18% of 60 2. 32% of 82 3. 77% of 144 4. 99% of 150 5. 52% of 52 6. 1.5% of 16 7. 41.7% of 88 = 10.8 = 26.24 = 110.88 = 148.5 = 527.04 = 24 = 36.08

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