Transcript percentage_multipliers

© T Madas
To convert a decimal into
a percentage, you multiply
the decimal by 100
0.3
x 100
To convert a percentage
into a decimal, you divide
the percentage by 100
÷ 100
30%
40%
0.45 x 100
45%
6%
÷ 100
0.05 x 100
5%
200%
÷ 100
1.5 x 100
150%
800%
÷ 100
x 100
400%
17.5%
÷ 100
31.8%
34.9%
÷ 100
4
0.318
x 100
0.4
0.06
2
8
0.175
0.349
© T Madas
The
decimal
form of ainto
percentage
is also
known as
To convert
a decimal
To convert
a percentage
the
percentage
multiplier
a percentage,
you
multiply . into a decimal, you divide
the decimal by 100
the percentage by 100
We
can use multipliers in calculations:
25% = 0.25
13% = 0.13
72.5% = 0.725
13.2% = 0.132
6.6% = 0.066
220% = 2.2
0.5% = 0.005
Find 25% of 456
0.25 x 456 = 114
Find 37% of 514
0.37 x 514 = 190.18
Find 6% of 348
0.06 x 348 = 20.88
© T Madas
The decimal form of a percentage is also known as
the percentage multiplier.
We can use multipliers in calculations:
25% = 0.25
13% = 0.13
72.5% = 0.725
13.2% = 0.132
6.6% = 0.066
220% = 2.2
Find 7.5% of 124
0.075 x 124 = 9.3
Find 200% of 356
2 x 356 = 712
0.5% = 0.005
© T Madas
Calculating
Percentages
using
Multipliers
© T Madas
Practice on using Percentage Multipliers
Calculate the following percentages by
using multipliers:
35% of 124:
0.35 x 124 = 43.4
43% of 220:
0.43 x 220 = 94.6
74% of 350:
0.74 x 350 = 259
13% of 270:
0.13 x 270 = 35.1
29% of 260:
0.29 x 260 = 75.4
65% of 480:
0.65 x 480 = 312
5% of 185:
0.05 x 185 = 9.25
7% of 631:
0.07 x 631 = 44.17
7.5% of 440:
0.075 x 440 = 33
5.5% of 820:
0.055 x 820 = 45.1
© T Madas
Practice on using Percentage Multipliers
Calculate the following percentages by
using multipliers:
65% of 144:
0.65 x 144 = 93.6
13% of 320:
0.13 x 320 = 41.6
54% of 360:
0.54 x 360 = 194.4
81% of 670:
0.81 x 670 = 542.7
8% of 250:
4.5% of 560:
0.08 x 250 = 20
0.045 x 560 = 25.2
17.5% of 820:
0.175 x 820 = 143.5
7.3% of 1450:
0.073 x 1450 = 105.85
11.5% of 444:
0.115 x 444 = 51.06
0.5% of 910:
0.005 x 910 = 4.55
© T Madas
Practice on using Percentage Multipliers
Find 12% of 140
16.8
Find 34% of 185
62.9
Find 22% of 387
85.14
Find 17.5% of 240 42
Find 35% of 96.4
33.74
Find 8.5% of 384
Find 72% of 855
615.6
Find 27.5% of 120 33
Find 41% of 390
159.9
Find 7.2% of 855
Find 26% of 307
79.82
Find 16.4% of 365 59.86
Find 9% of 110
9.9
Find 1.7% of 300
5.1
Find 12.5% of 68
8.5
Find 0.5% of 110
9.9
32.64
61.56
© T Madas
Practice on using Percentage Multipliers
Find 14% of 160
22.4
Find 35% of 284
99.4
Find 24% of 749
179.76
Find 17.5% of 320 56
Find 45% of 146.4 65.88
Find 8.5% of 384
10.71
Find 32% of 855
273.6
Find 27.5% of 360 99
Find 11% of 930
102.3
Find 8.2% of 900
Find 36% of 385
138.6
Find 18.4% of 565 103.96
Find 7% of 220
15.4
Find 0.5% of 360
Find 12.5% of 88
11
Find 0.25% of 400 1
73.8
1.8
© T Madas
Test
on calculating
Percentages
using
Multipliers
© T Madas
Practice on using Percentage Multipliers
Calculate the following percentages by
using multipliers:
35% of 124:
0.35 x 124 = 43.4
43% of 220:
0.43 x 220 = 94.6
74% of 350:
0.74 x 350 = 259
13% of 270:
0.13 x 270 = 35.1
29% of 260:
0.29 x 260 = 75.4
65% of 480:
0.65 x 480 = 312
5% of 185:
0.05 x 185 = 9.25
7% of 631:
0.07 x 631 = 44.17
7.5% of 440:
0.075 x 440 = 33
5.5% of 820:
0.055 x 820 = 45.1
© T Madas
Practice on using Percentage Multipliers
Calculate the following percentages by
using multipliers:
65% of 144:
0.65 x 144 = 93.6
13% of 320:
0.13 x 320 = 41.6
54% of 360:
0.54 x 360 = 194.4
81% of 670:
0.81 x 670 = 542.7
8% of 250:
4.5% of 560:
0.08 x 250 = 20
0.045 x 560 = 25.2
17.5% of 820:
0.175 x 820 = 143.5
7.3% of 1450:
0.073 x 1450 = 105.85
11.5% of 444:
0.115 x 444 = 51.06
0.5% of 910:
0.005 x 910 = 4.55
© T Madas
Practice on using Percentage Multipliers
Find 12% of 140
16.8
Find 34% of 185
62.9
Find 22% of 387
85.14
Find 17.5% of 240 42
Find 35% of 96.4
33.74
Find 8.5% of 384
Find 72% of 855
615.6
Find 27.5% of 120 33
Find 41% of 390
159.9
Find 7.2% of 855
Find 26% of 307
79.82
Find 16.4% of 365 59.86
Find 9% of 110
9.9
Find 1.7% of 300
5.1
Find 12.5% of 68
8.5
Find 0.5% of 110
9.9
32.64
61.56
© T Madas
Practice on using Percentage Multipliers
Find 14% of 160
22.4
Find 35% of 284
99.4
Find 24% of 749
179.76
Find 17.5% of 320 56
Find 45% of 146.4 65.88
Find 8.5% of 384
10.71
Find 32% of 855
273.6
Find 27.5% of 360 99
Find 11% of 930
102.3
Find 8.2% of 900
Find 36% of 385
138.6
Find 18.4% of 565 103.96
Find 7% of 220
15.4
Find 0.5% of 360
Find 12.5% of 88
11
Find 0.25% of 400 1
73.8
1.8
© T Madas
© T Madas
To convert any type of number
into a percentage you multiply
the number by 100
0.38 x 100 = 38%
0.213 x 100 = 21.3%
1.63
2
x 100 = 163%
x 100 = 200%
4/
7
x 100 =
¾
x 100 =
400/
7
300/
4
≈ 57.14%
= 75%
© T Madas
When you multiply a number by 1.1
you increase the number by ______of
0.1
your starting number
When you multiply a number by 0.9
you decrease the number by ______of
0.1
your starting number
© T Madas
When you multiply a number by 1.2
you increase the number by ______of
0.2
your starting number
When you multiply a number by 0.8
you decrease the number by ______of
0.2
your starting number
© T Madas
When you multiply a number by 1.15
you increase the number by ______of
0.15
your starting number
When you multiply a number by 0.85
you decrease the number by ______of
0.15
your starting number
We extend this idea to percentages
© T Madas
Examples on using Percentage Multipliers
Increase 5000 by 10%
5000 x 1.1
Increase 4500 by 15%
4500 x 1.15
Increase 1200 by 27%
1200 x 1.27
Decrease 750 by 20%
750 x 0.80
Decrease 1200 by 14%
1200 x 0.86
Decrease 12500 by 32%
12500 x 0.68
Increase 2000 by 17.5%
2000 x 1.175
Decrease 17000 by 5.5%
17000 x 0.945
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Using Multipliers for Percentage Changes
If an amount is increased by x % the new amount is
(100 + x )% of the original amount
Increase 9000 by 15%
100% + 15% = 115%
9000 x 1.15 = 10350
115% = 1.15
If an amount is decreased by x % the new amount
is (100 – x )% of the original amount
Decrease 4500 by 12%
100% – 12% = 88%
4500 x 0.88 = 7920
88% = 0.88
© T Madas
Calculating
Percentage
increases & decreases
using multipliers
© T Madas
Percentage Changes using Multipliers
Calculate the following percentages by
using multipliers:
Increase 220 by 15%:
220 x 1.15 = 253
Decrease 230 by 15%:
230 x 0.85 = 195.5
Increase 125 by 12%:
125 x 1.12 = 140
Decrease 180 by 9%:
180 x 0.91 = 163.8
Increase 320 by 22% : 320 x 1.22 = 390.4
Decrease 155 by 18%:
155 x 0.82 = 127.1
Increase 275 by 24%:
275 x 1.24 = 341
Decrease 725 by 25%:
725 x 0.75 = 543.75
Increase 520 by 35%:
520 x 1.35 = 702
Decrease 900 by 16%:
900 x 0.84 = 756
© T Madas
Percentage Changes using Multipliers
Calculate the following percentages by
using multipliers:
Increase 260 by 15%:
260 x 1.15 = 299
Decrease 450 by 12%:
450 x 0.88 = 396
Increase 225 by 16%:
225 x 1.16 = 261
Decrease 184 by 5%:
184 x 0.95 = 174.8
Increase 780 by 7% :
780 x 1.07 = 834.6
Decrease 265 by 18%:
265 x 0.82 = 217.3
Increase 430 by 8%:
430 x 1.08 = 464.4
Decrease 870 by 6%:
870 x 0.94 = 817.8
Increase 520 by 17.5%: 520 x 1.175 = 611
Decrease 900 by 5.5%:
900 x 0.945 = 850.5
© T Madas
Percentage increase & decrease using Multipliers
Increase 320 by 10%
352
Increase 175 by 15%
201.25
Increase 156 by 35%
210.6
Decrease 240 by 20% 192
Decrease 865 by 40%
519
Increase 125 by 12%
140
Increase 264 by 29%
340.56
Decrease 1008 by 7% 937.44
Decrease 298 by 13% 259.26
© T Madas
Percentage increase & decrease using Multipliers
Increase 340 by 15%
391
Increase 245 by 18%
289.1
Increase 825 by 34%
1105.5
Decrease 280 by 15%
238
Decrease 345 by 40%
207
Increase 9832 by 16%
11405.12
Increase 398 by 31%
521.38
Decrease 1538 by 5%
1461.1
Decrease 312 by 11%
277.68
© T Madas
Test on
Percentage
increases & decreases
using multipliers
© T Madas
Percentage Changes using Multipliers
Calculate the following percentages by
using multipliers:
Increase 220 by 15%:
220 x 1.15 = 253
Decrease 230 by 15%:
230 x 0.85 = 195.5
Increase 125 by 12%:
125 x 1.12 = 140
Decrease 180 by 9%:
180 x 0.91 = 163.8
Increase 320 by 22% : 320 x 1.22 = 390.4
Decrease 155 by 18%:
155 x 0.82 = 127.1
Increase 275 by 24%:
275 x 1.24 = 341
Decrease 725 by 25%:
725 x 0.75 = 543.75
Increase 520 by 35%:
520 x 1.35 = 702
Decrease 900 by 16%:
900 x 0.84 = 756
© T Madas
Percentage Changes using Multipliers
Calculate the following percentages by
using multipliers:
Increase 260 by 15%:
260 x 1.15 = 299
Decrease 450 by 12%:
450 x 0.88 = 396
Increase 225 by 16%:
225 x 1.16 = 261
Decrease 184 by 5%:
184 x 0.95 = 174.8
Increase 780 by 7% :
780 x 1.07 = 834.6
Decrease 265 by 18%:
265 x 0.82 = 217.3
Increase 430 by 8%:
430 x 1.08 = 464.4
Decrease 870 by 6%:
870 x 0.94 = 817.8
Increase 520 by 17.5%: 520 x 1.175 = 611
Decrease 900 by 5.5%:
900 x 0.945 = 850.5
© T Madas
Percentage increase & decrease using Multipliers
Increase 320 by 10%
352
Increase 175 by 15%
201.25
Increase 156 by 35%
210.6
Decrease 240 by 20% 192
Decrease 865 by 40%
519
Increase 125 by 12%
140
Increase 264 by 29%
340.56
Decrease 1008 by 7% 937.44
Decrease 298 by 13% 259.26
© T Madas
Percentage increase & decrease using Multipliers
Increase 340 by 15%
391
Increase 245 by 18%
289.1
Increase 825 by 34%
1105.5
Decrease 280 by 15%
238
Decrease 345 by 40%
207
Increase 9832 by 16%
11405.12
Increase 398 by 31%
521.38
Decrease 1538 by 5%
1461.1
Decrease 312 by 11%
277.68
© T Madas
© T Madas
What is the decimal you multiply with to …
… find 15% of a number 0.15
… increase a number by 12% 1.12
… decrease a number by 5% 0.95
… increase a number by 20% 1.2
… find 45% of a number 0.45
… decrease a number by 15% 0.85
… find 20% of a number 0.2
… increase a number by 50% 1.5
… decrease a number by 30% 0.7
… find 25% of a number 0.25
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What is the decimal you multiply with to …
… find 35% of a number 0.35
… increase a number by 35% 1.35
… decrease a number by 35% 0.65
… increase a number by 12% 1.12
… find 85% of a number 0.85
… decrease a number by 4% 0.96
… find 12.5% of a number 0.125
… increase a number by 5% 1.05
… decrease a number by 12% 0.88
… find 17.5% of a number 0.175
© T Madas
What is the decimal you multiply with to …
… find 22.5% of a number 0.225
… increase a number by 17.5% 1.175
… decrease a number by 11% 0.89
… increase a number by 12.5% 1.125
… find 95% of a number 0.95
… decrease a number by 24% 0.86
… find 7.5% of a number 0.075
… increase a number by 6.2% 1.062
… decrease a number by 65% 0.35
… find 1.2% of a number 0.012
© T Madas
© T Madas
What is the decimal you multiply with to …
… find 15% of a number 0.15
… increase a number by 12% 1.12
… decrease a number by 5% 0.95
… increase a number by 20% 1.2
… find 45% of a number 0.45
… decrease a number by 15% 0.85
… find 20% of a number 0.2
… increase a number by 50% 1.5
… decrease a number by 30% 0.7
… find 25% of a number 0.25
© T Madas
What is the decimal you multiply with to …
… find 35% of a number 0.35
… increase a number by 35% 1.35
… decrease a number by 35% 0.65
… increase a number by 12% 1.12
… find 85% of a number 0.85
… decrease a number by 4% 0.96
… find 12.5% of a number 0.125
… increase a number by 5% 1.05
… decrease a number by 12% 0.88
… find 17.5% of a number 0.175
© T Madas
What is the decimal you multiply with to …
… find 22.5% of a number 0.225
… increase a number by 17.5% 1.175
… decrease a number by 11% 0.89
… increase a number by 12.5% 1.125
… find 95% of a number 0.95
… decrease a number by 24% 0.86
… find 7.5% of a number 0.075
… increase a number by 6.2% 1.062
… decrease a number by 65% 0.35
… find 1.2% of a number 0.012
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© T Madas
Match with an arrow each statement to a calculation.
For each of the calculations that you did not pick, write
a statement involving percentages about what it could
possibly represent.
a
85 x 0.93
Find 7% of 85
b
85 x 1.07
Increase 85 by 7%
c
85 x 0.07
Decrease 85 by 7%
d
85 x 0.7
e
85 x 1.7
d 85 x 0.7
Find 70% of 85
e 85 x 1.7
Find 170% of 85
Decrease 85 by 30%
Increase 85 by 70%
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© T Madas