Cambridge IGCSE Mathematics · Syllabus 0580 · Number
Percentages
What is Percentages?
A percentage is a number of hundredths, so a percentage of a quantity is that quantity multiplied by the percentage over one hundred. Any percentage increase or decrease can be carried out in a single step by multiplying by one plus or minus the percentage as a decimal, and reversing such a change means dividing by that same multiplier rather than applying the opposite percentage.
This definition is part of the Number chapter in Cambridge IGCSE Mathematics.
Percentages in context
Fractions, decimals and percentages are one number wearing three coats. Choose the coat that suits the job: fractions for exact work and cancelling, decimals for ordering and calculator entry, percentages for comparison and change. The conversions themselves are only three operations — divide, use place value, and multiply or divide by 100 — and every one of them is reversible.