decimals and fractions

1. Unit 1
Decimals & Fractions
Presentation 1 Multiplying and Dividing Decimals
Presentation 2 Converting Fractions and Decimals
Presentation 3 Negative Numbers
Presentation 4 Operations with Negative Numbers
Presentation 5 Estimating Answers

2. Unit 1
Decimals & Fractions
Multiplying and Dividing Decimals

3. To multiply by 100, move the decimal point 2
places to the right, giving:
similarly

4. To divide by 100, move the decimal point 2
places to the left, giving:
similarly

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Multiplying and Dividing Decimals
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Presentation 2 Converting Fractions and Decimals
Presentation 3 Negative Numbers
Presentation 4 Operations with Negative Numbers
Presentation 5 Estimating Answers

6. Unit 1
Decimals & Fractions
Converting Fractions and
Decimals

7. Fractions to Decimals
Express as a decimal.
Here it is best to divide out:

8. Express as a decimal.
Here it is easier to make the denominator a
multiple of 10

9. Express as a decimal in its simplest
form

10. You have finished viewing the presentation
Converting Fractions and Decimals
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Presentation 1 Multiplying and Dividing Decimals
Presentation 3 Negative Numbers
Presentation 4 Operations with Negative Numbers
Presentation 5 Estimating Answers

11. Unit 1
Decimals & Fractions
Negative Numbers

12. Example 1
What is 15o
C less than 26o
C?
Solution
26o
C – 15o
C = 11o
C
Example 2
What is 15o
C less than 10o
C?
Solution
10o
C – 15o
C = – 5o
C

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Negative Numbers
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Presentation 1 Multiplying and Dividing Decimals
Presentation 2 Converting Fractions and Decimals
Presentation 4 Operations with Negative Numbers
Presentation 5 Estimating Answers

14. Unit 1
Decimals & Fractions
Operations with Negative
Numbers

15. Remember …
Example 1

16. Remember …
Example 2

17. Remember …
Example 3

18. Remember …
Example 4

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Operations with Negative Numbers
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Presentation 1 Multiplying and Dividing Decimals
Presentation 2 Converting Fractions and Decimals
Presentation 3 Negative Numbers
Presentation 5 Estimating Answers

20. Unit 1
Decimals & Fractions
Estimating Answers

21. It is important to be able to estimate
answers to complex calculations.
Without a calculator which of the answers is
equal to ?
A 1∙649 B 16∙494 C 164∙945

22. Without a calculator which of the answers is
equal to ?
You have to approximate each answer in the
calculation. Hence, for example
A 1∙649 B 16∙494 C 164∙945

23. You have finished viewing the presentation
Estimating Answers
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Return to the Start
Presentation 1 Multiplying and Dividing Decimals
Presentation 2 Converting Fractions and Decimals
Presentation 3 Negative Numbers
Presentation 4 Operations with Negative Numbers