Transcript Objectives: • Calculate percentages using non-calculator methods. • Calculate percentages less than 10% and values other than multiples of 10. Vocabulary:

Objectives:
• Calculate percentages using non-calculator methods.
• Calculate percentages less than 10% and values other than
multiples of 10.
Vocabulary:
T3.1B
20 is 50% of 40.
40
50
500
250
500 is 10% of 5000
120
720
70
60
50 is 20% of 250
120 is 25% of 480
90 is 5% of 1800
70 is 50% of 140
60 is 50% of 120
120 is 40% of 300
90
140
860
1800
20
5000
300
480
250 is 50% of 500
90 is 75% of 120
Find three more percentage relationships on the target board.
What is 10% of £380?
How did you work out 10% of £380?
How can you use the answer for 10% to find 20%?
20% = 10% + 10% = £38 + £38 = £76
How can you use 10% to find 30%?
30% = 10% + 10% + 10% = 3 x £38 = £114
W/S 3.1B
10%
60%
50%
20%
60
40%
30%
On a copy of the spider diagram fill in the amounts.
Answers:
10%
60%
6
36
50%
20%
30
60
12
40%
30%
24
18
How many times will 5% fit into 10%?
How can you work out 5% if you know 10%?
Find 5% of £240 – explain how you got your answer.
10% of £240 is £24
0%
so 5% of £240 is £12.
10%
100%
0
£240
£24
Find 5% of £720 – explain how you got the answer.
10% of £720 is £72
so 5% of £720 is £36
T3.2B
Find 5% of each amount as it is highlighted
400
50
1200
700
500
24
72
600
80
140
40
1800
20
800
300
120
How can you find 15% of an amount?
15% can be found by adding 10% and 5% together.
Find 15% of 300 – explain your working.
10% of 300 is 30
5% of 300 is 15
15% is 30 + 15 = 45
10% 15%
0%
100%
0
300
30
45
T3.2B
Find 15% of each number as it is highlighted.
400
50
1200
700
500
24
72
600
80
140
40
1800
20
800
300
120
W/S3.2B
25%
15%
10%
17.5%
5%
60
45%
95%
35%
55%
Complete a spider diagram like the one above.
Answers
25%
15%
10%
9
15
6
17.5%
10.5
5%
3
60
57
45%
95%
27
21
35%
33
55%
If I can find 10% how can I find 1%?
Example: Find 1% of £350
Method 1
1% is the same as 1/100th so I can divide by 100
£350 ÷ 100 = £3.5 written £3.50
Method 2
1% is 10% divided by 10.
10% of £350 is £35 so 1% is £35 ÷10 = £3.5 or £3.50
T3.1B
State 1% of each number as it is highlighted.
40
500
120
70
50
250
720
60
90
140
860
1800
20
5000
300
480
Objectives:
• Calculate percentages using non-calculator methods.
• Calculate percentages less than 10% and values other than
multiples of 10.
Vocabulary:
Thank you
for your
attention