Study Guide G11 ~ Mathematical Literacy
Unit
1
Part 4: Percentages A percentage is a way of expressing the parts of a whole (the numerator) as a value out of 100. It is always written with the % symbol directly after the number. A percentage can also be written as a fraction. The denominator will always be 100. The term ‘per cent’ derives from the Latin word per centum, which means ‘per hundred’ or ‘for every hundred’. Percentages can be expressed as a common fraction or as a decimal number, 83
e.g. 83% = 100 OR = 0,83.
4.1 Calculation of percentage To calculate a percentage of an amount, write the per cent as a fraction and multiply by the amount. per cent × amount 100 EXAMPLES 4.1.1
Calculate 25% of R5 000,00. Note: The word ‘of’ means multiplication. 25
100
4.1.2
× R5 000 = R1 250,00
Sequence on calculator: (25 ÷ 100) × 5 000 = 28
Thandi gets 40 in a Mathematical Literacy test.
What is her percentage for the test? 28 40
× 100 = 70%
Sequence on calculator: (28 ÷ 40) × 100 =
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