1. Rounding to 2 sig. figures
Title: Standard Form
Side Heading:
Rounding to 2 sig. figures
Project the link, allow pupils to watch (in awe!) then freeze. Ask to round to 2 s.f.

2. Learning Outcomes
All will be able to write very large numbers in standard form
Most will be able to write very small numbers in standard form
Some will be able to carry out multiplication and division sums in standard form

3. Look at how these numbers have been broken down:
= 5 × 100
= 5 × 1 000
= 5 ×
= 5 × 102
= 5 × 103
= 5 × 104
you know how to write
these as powers of 10

4. What about these?
= 5.5 × 102
550
5 500
55 000
= 5.5 × 100
= 5.5 × 1 000
= 5.5 × 103
= 5.5 ×
= 5.5 × 104

5. × a number between 1 a power and 10 of ten but not including 10
Standard form is:
a number
between 1
and 10 ×
a power
of ten
but not including 10
positive or negative

7.
4 .504
x 109
Number between 1 and 10
Power of 10

8. True or false

9. In standard form = 1.2 x 104

10. In standard form = 13 x 105

11.
Extension
The distance of Earth from the sun is km. Write this number in standard form.   
x 10⁹ km is the distance of Neptune from the sun. Write this in standard form.

12. Standard form
a  10n where a is between 1 and 10 (1≤a<10) and n is a positive or negative integer
Worked examples
4  106
9.25  10–4
3.681  10–7
7.3  105 = = = =

15. Connect four - Standard form
Convert Ordinary Numbers into Standard From (Tiles 1 to 21)
Evaluate these Standard Form Calculations (Tiles 22 to 42)
Connect four - Standard form 36 37 38 39 40 41 42 29 30 31 32 33 34 35 22 23 24 25 26 27 28 15
21.1 16
211.3 17
111.1 18
70.01 19
201.1 20
11.01 21
0.009 8
0.125 9
0.025 10
0.006 11
0.15 12
0.201 13
0.0222 14
0.0101 1
123 2 3
902 4
301 5
1701 6
111 7
1001
0.11 20
1150
1711
0.31
0.004
0.05
ans
ans
ans
ans
ans
ans
ans 10
0.0071
0.0012
0.05 30
800
2120
ans
ans
ans
ans
ans
ans
ans
0.05
1000
500
0.002
0.7
8000
0.003
ans
ans
ans
ans
ans
ans
ans
2.11 X 10
2.113 X 102
1.111 X 102
7.001 X 10
2.011 X 102
1.101 X 10
9X 10-2
ans
ans
ans
ans
ans
ans
ans
1.25 X 10-1
2.5 X 10-2
6 X 10-3
1.5 X 10-1
2.01 X 10-1
2.22 X 10-2
1.01 X 10-2
ans
ans
ans
ans
ans
ans
ans
1.23 X 102
2.3 X 10
9.02 X 102
3.01 X 102
1.701 X 103
1.11 X 102
1.001 X 103
ans
ans
ans
ans
ans
ans
ans 15
09/11/2019

17. Starter: Work out the answers to the following
Easier
Challenge