# INTRODUCTION TO DECIMALS.

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INTRODUCTION TO DECIMALS

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

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

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

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

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

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