starter however you like, multiply out: 11 x 25 11 x 71 11 x 34 11 x 42 11 x 1411 x 83
TRANSCRIPT
Starter• However you like, multiply out:
11 x 25 11 x 71
11 x 34 11 x 42
11 x 14 11 x 83
Mr. Cosgrove
Percentages
• Lesson Objective: To calculate the percentage of an amount WITHOUT a calculator.
• Success CriteriaDivide by 10 Find 10%, 20%, 30% etc.Know how to find 5%, 1% and combinations
Friday May 9 2014
Mr. Cosgrove
What will we learn today?
A question about today’s lesson you would like answered
Two things I know already
Three new things I have learned
To be completed at THE END
NAME:_____________
Why do we need to know percentages of amounts?
To calculate percentages:
• We need to make sure we can divide by 10.
• 350 ÷ 10• 9000 ÷ 10• 62900 ÷ 10• 30 ÷ 10• 7 ÷ 10• 21.2 ÷ 10
Percentages of Amounts
Example: How can you calculate 10% of 80?
100% = 80
10% = 8÷ 10 ÷ 10
Finding 10% of a number
• 10 % is the same as dividing by 10.
On your own:a) 10% of 350 kg = b) 10% of 20 L =c) 10% of 10 000 hours =d) 10% of £900?
Percentages of Amounts
On your own…
(a) (b)
10%
(c)
OR Move decimal point one left
÷ 10
10% of £40 10% of $180 10% of £57 (d)10% of £472
(e) (f) (g)20% of 50m 20% of 190km 30% of 40cm (h)30% of 90mm
(i) (j) (k)40% of 80min 60% of 70hours 80% of 20days (l) 90% of 30years
= £4 = $18 = £5.70 = £47.20
10% = 5m10% = 5m
10% = 19km10% =19km
10% = 4cm10% =4cm
10% = 9mm10% = 9mm
x4 10% = 8min40% =
x432min
x6 10% = 7hours60% =
x642hours x8
10% = 2days80% =
x816days
x9 10% = 3years90% =
x927years
10% = 4cm 10% = 9mm
Core
Extension
Kil ler
Percentages of Amounts
• If you can find 10% of a number, you can find 5% and 1%
• How?
Percentages of Amounts
Example: Find 5% of 140100% = 140
10% =
5% =
14
7
÷ 10 ÷ 10
÷ 2 ÷ 2
Percentages of Amounts
Example: Find 1% of 1500100% = 1500
10% = 150
1% = 15
÷ 10 ÷ 10
÷ 10 ÷ 10
Can you use this information to find:
• 12% of 1800?
10% = 1801% = 18
12% = 10% + 1% + 1%12% = 180 + 18 + 18
12% = 216
Can you use this information to find:
• 35% of 280
10% = 285% = 14
35% = 10% + 10% + 10% + 5%35% = 28 + 28 + 28 + 14
35% = 98
Core KILLER
1) 28% of £200 =
2) 63% of £500 =
3) 19% of £400 =
4) 37% of £80 =
5) 82% of £54 =
6) 51% of £40 =
7) 4% of £90 =
8) 23% of £6 =
1) 10% of £80 =
2) 10% of £130 =
3) 10% of £36 =
4) 20% of £60 =
5) 20% of £62 =
6) 30% of £70 =
7) 30% of £180 =
8) 40% of £360 =
Extension
1) 62% of £90 =
2) 71% of £410 =
3) 85% of £40 =
4) 90% of £800 =
5) 5% of £1480 =
6) 35% of £80 =
7) 45% of £90 =
8) 15% of £400 =
Independent Task
How can we use this today?
£700
Percentages
• Lesson Objective: To calculate the percentage of an amount WITHOUT a calculator.
• Success CriteriaDivide by 10 Find 10%, 20%, 30% etc.Know how to find 5%, 1% and combinations
Friday May 9 2014
Mr. Cosgrove
What will we learn today?
A question about today’s lesson you would like answered
Two things I know already
Three new things I have learned