1. INTRODUCTION TO
DECIMALS

2. Definitions and Place Value
When we write a number like how do we know what it means ? The answer is PLACE VALUE ! Decimal Point (>1 . <1)
6 x 1/1000
4 x 10
5 x 1
8 x 1/100
7 x 1/10

3. Powers of 10
Remember that 100, 10, 1, 1/10, 1/100, 1/1000 in our decimal places are really powers of 10 ! 10 to the power 2 = to the power 1 = to the power 0 = 1 10 to the power -1 = 1/10 10 to the power -2 = 1/ to the power -3 = 1/1000

4. Place Value and Powers of Ten
What does mean ? Hint: 2 x
103
101
10-1
10-3
102
100
10-2
10-4
Decimal Point

5. Quick Exercise Write the following as a sum of powers of 10 200 100.5
900.02
30.058

6. Answers Write the following as a sum of powers of 10
x x (100 = 1)
x x 10-1
x x 10-2
x x x 10-3

7. Summary Decimal numbers depend on Place Value
Numbers to the left of the Decimal Point are
> 1 (greater than 1) and to the right are < 1 (less than 1 – like fractions !)
Each column is ten times different to its neighbours