# RATIONAL AND IRRATIONAL NUMBERS

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RATIONAL AND IRRATIONAL NUMBERS

Recurring decimals

Recurring decimals contain digits that are repeated over and over again.
are all examples of recurring decimals Dots are used to show how the decimals recur.

Changing recurring decimals to fractions
1 Change to a fraction. let multiply both sides of the equation by 10 write underneath subtract the two equations divide both sides by 9 If 1 digit recurs multiply by 10. If 2 digits recur multiply by 100. If 3 digits recur multiply by 1000. Answer:

Changing recurring decimals to fractions
2 Change to a fraction. let multiply both sides of the equation by 100 write underneath subtract the two equations divide both sides by 99 If 1 digit recurs multiply by 10. If 2 digits recur multiply by 100. If 3 digits recur multiply by 1000. Answer:

Changing recurring decimals to fractions
3 Change to a fraction. let multiply both sides of the equation by 1000 write underneath subtract the two equations divide both sides by 999 If 1 digit recurs multiply by 10. If 2 digits recur multiply by 100. If 3 digits recur multiply by 1000. Answer:

Changing recurring decimals to fractions
4 Change to a fraction. let multiply both sides of the equation by 100 write underneath subtract the two equations divide both sides by 99 If 1 digit recurs multiply by 10. If 2 digits recur multiply by 100. If 3 digits recur multiply by 1000. Answer:

The set of real numbers can be divided into two sets:
RATIONAL NUMBERS and IRRATIONAL NUMBERS Numbers that can be written in the form a . b Numbers that cannot be written in the form a . b

Rational numbers include:
all fractions all integers all mixed numbers all terminating decimals all recurring decimals some square roots some cube roots

Irrational numbers include:
some square roots some cube roots some trig ratios

1 Which of these numbers are irrational numbers?

2 Write each of these numbers in the correct place on the Venn diagram.
Rational numbers Integers

3 Is x rational or irrational for this triangle?
x cm 10 cm 24 cm Using Pythagoras Answer: x is rational

4 Is x rational or irrational for this triangle?
12 cm 4 cm x cm Using Pythagoras Answer: x is irrational