1. Work out (3.2 × 105) – (2.89 × 104) Give your answer in standard form
Classwork/Homework
Work out (3.2 × 105) – (2.89 × 104) Give your answer in standard form
b) Write the biggest number and the smallest number as an ordinary number:
c) Work out 4 x 108 x 5 x 10-6.Give your answer in standard form
d) Work out 7 x 103 x 2 x 10-5.Give your answer in standard form
8.3 x x x 10-3
9.245 x x x 10-2

2. Work out (3.2 × 105) – (2.89 × 104) Give your answer in standard form
Classwork/Homework
Work out (3.2 × 105) – (2.89 × 104) Give your answer in standard form
– =
 x 105
b) Write the biggest number and the smallest number as an ordinary number:

3. Classwork/Homework
c) Work out 4 x 108 x 5 x 10-6.Give your answer in standard form (4 x 5) x (108 x 10-6) (20) x (108+-6) 20 x x 103 (2 + 1 = 3) Answer: 2 x 103

4. Classwork/Homework
d) Work out 7 x 103 x 2 x 10-5.Give your answer in standard form (7 x 2) x (103 x 10-5) (14) x (103+-5) 14 x x 10-1 ( = -1) Answer: 1.4 x 10-1

5. N E T S A T O M I I T O M I X P O P A N I R D O N G U N I R
Guess the Anagrams
N E T S A T O M I I T O M I X P O P A N I R D O N G U N I R
What do they mean? Why are they useful?

6. 0.003  leading zeros are not considered significant
Significant Figures
Significant figures are those numbers considered to be important because they give you useful information
All non-zero digits are significant
Zeros aren’t always significant – it depends on their position in the number
Zeros before the first non-zero digit are not significant
203  significant
0.003  leading zeros are not considered significant
To compare two numbers you would need the 3
To compare two numbers for 203 the 0 plays an important role

7. Significant Figures
The first significant figure is always the first non-zero digit you come across (from left to right)
The second significant figure is the digit next to the first significant figure and so on.
We often shorten significant figures to s.f.

8. The second, third and fourth significant figures are the digits immediately following the first significant figure, including zeros.
For example,
This is the first significant figure
This is the third significant figure
This is the second significant figure
This is the fourth significant figure
and
This is the first significant figure

9. Important Point
When rounding to a number of significant figures: The size of your rounded number (your answer) should be a similar size to the number in the question! Ex. Round  Answer 33
YOU CANT BE ASKED TO ROUND AND THE ANSWER IS 30 !

10. ALL THE NUMBERS AFTER WILL BECOME ZERO
Significant Figures
Round to 2 significant figures
2nd significant figure, this will stay a 7 or go to 8 depending on what the next number is
1st significant figure
ALL THE NUMBERS AFTER WILL BECOME ZERO
Round to 2 significant figures=
or just 17!

11. It’s more than 4 so we round up!
Round to 1 s.f. 3 7 8 5 4 3 7
Look at the next number
It’s more than 4 so we round up!

12. It’s less than 5 so we round down!
Round to 3 s.f. 3 7 8 4 3 7
Look at the next number
It’s less than 5 so we round down!

13. It’s more than 4 so we round up!
Round to 2 s.f. . 2 9 8 9
Look at the next number
It’s more than 4 so we round up!

14. It’s more than 4 so we round up!
Round to 3 s.f. . 2 9 8 7
Look at the next number
It’s more than 4 so we round up!

15. Note
If you are rounding to say 3 significant figures, the answer must have AT LEAST 3 significant figures!

16. Homework STUDY what we have covered so far WORKING WITH NUMBERS
Positive indices (find the value & write index form)
Multiplying and Dividing Indices
Negative and Zero Indices
Standard form (big numbers)
Standard form (small numbers)
Rounding to Significant Figures