We are learning to find percentages
of 3 digit numbers.
What does % mean?
per
for every
cent
100
To find 1% of a number ÷ by 100
Find 1% of 225
225 ÷ 100
(move all digits 2
places to the right)
225.
2 .25
1% of 225 =
To find 10% of a number ÷ by 10
Find 10% of 376
376 ÷ 10
(move all digits 1
place to the right)
376.
37.6
10% of 376 =
Can we use this information
To find 11% of a number?
10% + 1% = 11%
Find 11% of 352
352 ÷ 100 = 3.52
352.
3.52
352 ÷ 10 = 35.2
352.
3 5.2
3.52
+
35.2
38 .72
Find 2% of 453
1% of 453
1% x 2 = 2%
453 ÷ 100 =4.53
The decimal point goes
between the 9 and the 0.
There are 2 digits after the
decimal point in the sum
so we need 2 digits after
the decimal point in the answer
4.53
x 2
1
9.0 6
2% of 453 =
2x3=6
2 x 5 = 10
(carry the 1)
2x4=8+1=9
Use these methods to find
12% of 563
Hint: add together
10%, 1% and 1%
56.3 + 5.63 + 5.63 =
16% of 285
Hint: add together
10%, 6 x 1%
28.5 + (6 x 2.85) =
Can you find
20% of 621?
Hint: 20% =
10% + 10%
or 10% x 2
621 ÷ 10 = 62.1
62.1
+
62.1
124.2
62.1
x 2
124.2
20% of 621 = 124.2