To convert a decimal into a percentage, you multiply the
decimal by 100 0.3 x 100 30% 0.45 x 100 45% 0.05 x 100 5% 1.5 x 100
150% 4 x 100 400% 0.318 x 100 31.8% To convert a percentage into a
decimal, you divide the percentage by 100 40% 6% 200% 800% 17.5%
34.9% 100 0.4 0.06 2 8 0.175 0.349
Slide 3
T Madas 25% = 13% 72.5% = 13.2% 6.6% = 220% 0.5% = 0.25 = 0.13
0.725 = 0.132 0.066 = 2.2 0.005 Find 25% of 456 0.25x 456= 114 Find
37% of 514 0.37x 514= 190.18 Find 6% of 348 0.06x 348= 20.88 To
convert a decimal into a percentage, you multiply the decimal by
100 To convert a percentage into a decimal, you divide the
percentage by 100 The decimal form of a percentage is also known as
the percentage multiplier. We can use multipliers in
calculations:
Slide 4
T Madas Find 7.5% of 124 0.075x 124= 9.3 Find 200% of 356 2x
356= 712 25% = 13% 72.5% = 13.2% 6.6% = 220% 0.5% = 0.25 = 0.13
0.725 = 0.132 0.066 = 2.2 0.005 The decimal form of a percentage is
also known as the percentage multiplier. We can use multipliers in
calculations:
Slide 5
T Madas Calculating Percentages using Multipliers
Slide 6
T Madas Practice on using Percentage Multipliers Calculate the
following percentages by using multipliers: 35% of 124: 43% of 220:
74% of 350: 13% of 270: 29% of 260: 65% of 480: 5% of 185: 7% of
631: 7.5% of 440: 5.5% of 820: 0.35 0.43 0.74 0.13 0.29 0.65 0.05
0.07 0.075 0.055 x 124 = x 220 = x 350 = x 270 = x 260 = x 480 = x
185 = x 631 = x 440 = x 820 = 43.4 94.6 259 35.1 75.4 312 9.25
44.17 33 45.1
Slide 7
T Madas Practice on using Percentage Multipliers Calculate the
following percentages by using multipliers: 65% of 144: 13% of 320:
54% of 360: 81% of 670: 8% of 250: 4.5% of 560: 17.5% of 820: 7.3%
of 1450: 11.5% of 444: 0.5% of 910: 0.65 0.13 0.54 0.81 0.08 0.045
0.175 0.073 0.115 0.005 x 144 = x 320 = x 360 = x 670 = x 250 = x
560 = x 820 = x 1450 = x 444 = x 910 = 93.6 41.6 194.4 542.7 20
25.2 143.5 105.85 51.06 4.55
Slide 8
T Madas Practice on using Percentage Multipliers Find 12% of
14016.8 Find 34% of 18562.9 Find 22% of 38785.14 Find 35% of
96.433.74 Find 72% of 855615.6 Find 41% of 390159.9 Find 26% of
30779.82 Find 9% of 1109.9 Find 12.5% of 688.5 Find 17.5% of 24042
Find 8.5% of 38432.64 Find 27.5% of 12033 Find 7.2% of 85561.56
Find 16.4% of 36559.86 Find 1.7% of 3005.1 Find 0.5% of 1109.9
Slide 9
T Madas Find 14% of 16022.4 Find 35% of 28499.4 Find 24% of
749179.76 Find 45% of 146.465.88 Find 32% of 855273.6 Find 11% of
930102.3 Find 36% of 385138.6 Find 7% of 22015.4 Find 12.5% of 8811
Find 17.5% of 32056 Find 8.5% of 38410.71 Find 27.5% of 36099 Find
8.2% of 90073.8 Find 18.4% of 565103.96 Find 0.5% of 3601.8 Find
0.25% of 4001 Practice on using Percentage Multipliers
Slide 10
T Madas Test on calculating Percentages using Multipliers
Slide 11
T Madas Practice on using Percentage Multipliers Calculate the
following percentages by using multipliers: 35% of 124: 43% of 220:
74% of 350: 13% of 270: 29% of 260: 65% of 480: 5% of 185: 7% of
631: 7.5% of 440: 5.5% of 820: 0.35 0.43 0.74 0.13 0.29 0.65 0.05
0.07 0.075 0.055 x 124 = x 220 = x 350 = x 270 = x 260 = x 480 = x
185 = x 631 = x 440 = x 820 = 43.4 94.6 259 35.1 75.4 312 9.25
44.17 33 45.1
Slide 12
T Madas Practice on using Percentage Multipliers Calculate the
following percentages by using multipliers: 65% of 144: 13% of 320:
54% of 360: 81% of 670: 8% of 250: 4.5% of 560: 17.5% of 820: 7.3%
of 1450: 11.5% of 444: 0.5% of 910: 0.65 0.13 0.54 0.81 0.08 0.045
0.175 0.073 0.115 0.005 x 144 = x 320 = x 360 = x 670 = x 250 = x
560 = x 820 = x 1450 = x 444 = x 910 = 93.6 41.6 194.4 542.7 20
25.2 143.5 105.85 51.06 4.55
Slide 13
T Madas Practice on using Percentage Multipliers Find 12% of
14016.8 Find 34% of 18562.9 Find 22% of 38785.14 Find 35% of
96.433.74 Find 72% of 855615.6 Find 41% of 390159.9 Find 26% of
30779.82 Find 9% of 1109.9 Find 12.5% of 688.5 Find 17.5% of 24042
Find 8.5% of 38432.64 Find 27.5% of 12033 Find 7.2% of 85561.56
Find 16.4% of 36559.86 Find 1.7% of 3005.1 Find 0.5% of 1109.9
Slide 14
T Madas Find 14% of 16022.4 Find 35% of 28499.4 Find 24% of
749179.76 Find 45% of 146.465.88 Find 32% of 855273.6 Find 11% of
930102.3 Find 36% of 385138.6 Find 7% of 22015.4 Find 12.5% of 8811
Find 17.5% of 32056 Find 8.5% of 38410.71 Find 27.5% of 36099 Find
8.2% of 90073.8 Find 18.4% of 565103.96 Find 0.5% of 3601.8 Find
0.25% of 4001 Practice on using Percentage Multipliers
Slide 15
T Madas
Slide 16
To convert any type of number into a percentage you multiply
the number by 100 FACT 0.213x 100 =21.3% 1.63 x 100 = 163% 0.38x
100 =38% 2x 100 =200% 4/74/7 x 100 = 57.14% 400 / 7 x 100 = 300 / 4
=75%
Slide 17
T Madas When you multiply a number by 1.1 you increase the
number by ______of your starting number 0.1 When you multiply a
number by 0.9 you decrease the number by ______of your starting
number
Slide 18
T Madas When you multiply a number by 1.2 you increase the
number by ______of your starting number 0.2 When you multiply a
number by 0.8 you decrease the number by ______of your starting
number
Slide 19
T Madas When you multiply a number by 1.15 you increase the
number by ______of your starting number 0.15 When you multiply a
number by 0.85 you decrease the number by ______of your starting
number We extend this idea to percentages
Slide 20
T Madas Increase 5000 by 10% Increase 4500 by 15% Increase 1200
by 27% Decrease 750 by 20% Decrease 1200 by 14% Decrease 12500 by
32% Increase 2000 by 17.5% Decrease 17000 by 5.5% 5000 x 1.1 4500 x
1.15 1200 x 1.27 750 x 0.80 1200 x 0.86 12500 x 0.68 2000 x 1.175
17000 x 0.945 Examples on using Percentage Multipliers
Slide 21
T Madas If an amount is increased by x % the new amount is (100
+ x )% of the original amount If an amount is decreased by x % the
new amount is (100 x )% of the original amount Increase 9000 by 15%
100% + 15% = 115% 115% = 1.15 9000 x 1.15 = 10350 Decrease 4500 by
12% 100% 12% = 88% 88% = 0.88 4500 x 0.88 = 7920 Using Multipliers
for Percentage Changes
Slide 22
T Madas Calculating Percentage increases & decreases using
multipliers
Slide 23
T Madas Calculate the following percentages by using
multipliers: Increase 220 by 15%: Decrease 230 by 15%: Increase 125
by 12%: Decrease 180 by 9%: Increase 320 by 22% : Decrease 155 by
18%: Increase 275 by 24%: Decrease 725 by 25%: Increase 520 by 35%:
Decrease 900 by 16%: 220 230 125 180 320 155 275 725 520 900 x 1.15
= x 0.85 = x 1.12 = x 0.91 = x 1.22 = x 0.82 = x 1.24 = x 0.75 = x
1.35 = x 0.84 = 253 195.5 140 163.8 390.4 127.1 341 543.75 702 756
Percentage Changes using Multipliers
Slide 24
T Madas Calculate the following percentages by using
multipliers: Increase 260 by 15%: Decrease 450 by 12%: Increase 225
by 16%: Decrease 184 by 5%: Increase 780 by 7% : Decrease 265 by
18%: Increase 430 by 8%: Decrease 870 by 6%: Increase 520 by 17.5%:
Decrease 900 by 5.5%: 260 450 225 184 780 265 430 870 520 900 x
1.15 = x 0.88 = x 1.16 = x 0.95 = x 1.07 = x 0.82 = x 1.08 = x 0.94
= x 1.175 = x 0.945 = 299 396 261 174.8 834.6 217.3 464.4 817.8 611
850.5 Percentage Changes using Multipliers
Slide 25
T Madas 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 Percentage increase & decrease using
Multipliers Decrease 298 by 13%259.26
Slide 26
T Madas 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 Percentage
increase & decrease using Multipliers
Slide 27
T Madas Test on Percentage increases & decreases using
multipliers
Slide 28
T Madas Calculate the following percentages by using
multipliers: Increase 220 by 15%: Decrease 230 by 15%: Increase 125
by 12%: Decrease 180 by 9%: Increase 320 by 22% : Decrease 155 by
18%: Increase 275 by 24%: Decrease 725 by 25%: Increase 520 by 35%:
Decrease 900 by 16%: 220 230 125 180 320 155 275 725 520 900 x 1.15
= x 0.85 = x 1.12 = x 0.91 = x 1.22 = x 0.82 = x 1.24 = x 0.75 = x
1.35 = x 0.84 = 253 195.5 140 163.8 390.4 127.1 341 543.75 702 756
Percentage Changes using Multipliers
Slide 29
T Madas Calculate the following percentages by using
multipliers: Increase 260 by 15%: Decrease 450 by 12%: Increase 225
by 16%: Decrease 184 by 5%: Increase 780 by 7% : Decrease 265 by
18%: Increase 430 by 8%: Decrease 870 by 6%: Increase 520 by 17.5%:
Decrease 900 by 5.5%: 260 450 225 184 780 265 430 870 520 900 x
1.15 = x 0.88 = x 1.16 = x 0.95 = x 1.07 = x 0.82 = x 1.08 = x 0.94
= x 1.175 = x 0.945 = 299 396 261 174.8 834.6 217.3 464.4 817.8 611
850.5 Percentage Changes using Multipliers
Slide 30
T Madas 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 Percentage increase & decrease using
Multipliers Decrease 298 by 13%259.26
Slide 31
T Madas 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 Percentage
increase & decrease using Multipliers
Slide 32
T Madas
Slide 33
find 15% of a number increase a number by 12% decrease a number
by 5% increase a number by 20% find 45% of a number decrease a
number by 15% find 20% of a number increase a number by 50%
decrease a number by 30% find 25% of a number What is the decimal
you multiply with to 0.15 1.12 0.95 1.2 0.45 0.85 0.2 1.5 0.7
0.25
Slide 34
T Madas find 35% of a number increase a number by 35% decrease
a number by 35% increase a number by 12% find 85% of a number
decrease a number by 4% find 12.5% of a number increase a number by
5% decrease a number by 12% find 17.5% of a number What is the
decimal you multiply with to 0.35 1.35 0.65 1.12 0.85 0.96 0.125
1.05 0.88 0.175
Slide 35
T Madas find 22.5% of a number increase a number by 17.5%
decrease a number by 11% increase a number by 12.5% find 95% of a
number decrease a number by 24% find 7.5% of a number increase a
number by 6.2% decrease a number by 65% find 1.2% of a number What
is the decimal you multiply with to 0.225 1.175 0.89 1.125 0.95
0.86 0.075 1.062 0.35 0.012
Slide 36
T Madas
Slide 37
find 15% of a number increase a number by 12% decrease a number
by 5% increase a number by 20% find 45% of a number decrease a
number by 15% find 20% of a number increase a number by 50%
decrease a number by 30% find 25% of a number What is the decimal
you multiply with to 0.15 1.12 0.95 1.2 0.45 0.85 0.2 1.5 0.7
0.25
Slide 38
T Madas find 35% of a number increase a number by 35% decrease
a number by 35% increase a number by 12% find 85% of a number
decrease a number by 4% find 12.5% of a number increase a number by
5% decrease a number by 12% find 17.5% of a number What is the
decimal you multiply with to 0.35 1.35 0.65 1.12 0.85 0.96 0.125
1.05 0.88 0.175
Slide 39
T Madas find 22.5% of a number increase a number by 17.5%
decrease a number by 11% increase a number by 12.5% find 95% of a
number decrease a number by 24% find 7.5% of a number increase a
number by 6.2% decrease a number by 65% find 1.2% of a number What
is the decimal you multiply with to 0.225 1.175 0.89 1.125 0.95
0.86 0.075 1.062 0.35 0.012
Slide 40
T Madas
Slide 41
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.
Decrease 85 by 7% a 85 x 0.93 b 85 x 1.07 c 85 x 0.07 d 85 x 0.7 e
85 x 1.7 Increase 85 by 7% Find 7% of 85 d 85 x 0.7 Find 70% of 85
Decrease 85 by 30% e 85 x 1.7 Find 170% of 85 Increase 85 by
70%
