# Lesson: Checking Methods L1-L2

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Slide 1: Slide
MathematicsLower Secondary (Key Stage 3)

This lesson contains 24 slides, with interactive quizzes and text slides.

Lesson duration is: 60 min

## Items in this lesson

#### Slide 5 -Slide

What is the most significant number in the number 789.65.
A
7
B
8
C
9
D
6

#### Slide 8 -Slide

What is 178 rounded to 1 significant figure
A
170
B
180
C
200
D
100

#### Slide 9 -Quiz

What is 3564 rounded to 1 significant figure
A
3000
B
4000
C
3600
D
3500

#### Slide 11 -Slide

Without working out the exact answer use estimation to work out which answer is the most likely to be correct to the question below
397 + 209
A
606
B
806
C
506
D
706

#### Slide 12 -Quiz

What is 543.50 to 1 significant figure,
A
500
B
540
C
550
D
600

#### Slide 13 -Quiz

Which of the following would be the best estimate for
1.9 x 197.6
A
40
B
400
C
4000
D
40,000

#### Slide 14 -Quiz

Craig buys 17 bottles of water at £1.62 each. Which calculation should Craig use to estimate the total cost?
A
17 x 1.62
B
17 x 1.60
C
20 x 2
D
20 x 1.62

#### Slide 15 -Quiz

Mr Blevins wants to buy a revision guide for each student.
There are 138 pupils.
The revision guides cost £3.75 each. Estimate how much the revision guides cost in total.

#### Slide 16 -Open question

Joe drives around 82 miles each week. Estimate how many miles Joe drives in a year.

#### Slide 17 -Open question

Jack needs to work out the area of a hall. he knows if he multiplies the length by the width he will get the area. The width is 4.4 metres and the length is 22.7 metres. Estimate the area of the hall.

34 x ? = 204
A
8
B
7
C
6
D
9

? x 6 = 128
A
15
B
16
C
17
D
18

? x 8= 416
A
54
B
52
C
56
D
58

#### Slide 23 -Quiz

Joe is asked to work out how many cinema tickets costing £4.50 she can buy with £144. She carries out the calculation below.
£144 ÷ 4.50 = 32
Write an inverse calculation to check Jo's answer.