(KS2, Year 3)

The Lesson

A percentage is a part of a whole. It expresses a part of a whole number as parts out of 100. A percentage is shown by the symbol % (said as "percent").

Dictionary Definition

The Merriam-Webster dictionary defines a percentage as "a part of a whole expressed in hundredths."

Interactive Widget

Use this interactive widget to watch the shapes fill by the percentage specified and the sums complete automatically. Simply click in the percentage bar at the top of the shaded area.
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Turn your phone on its side to use this widget.

A Real Example of a Percentage

A percentage is written as a number followed by the percentage symbol %:

This is 20% (said as "20 percent"). It means 20 parts out of 100.

A Real Example of What a Percentage Means

Imagine you were given 20% in a mathematics exam. You would have got 20 out of every 100 marks.
  • If there were 100 marks, you would have got 20 marks.
  • If there were 200 marks, you would have got 40 marks.
  • If there were 50 marks, you would have got 10 marks.

Visualizing Percentages

A percentage shows how many parts out of a 100. A grid with 100 squares is a useful way of visualizing percentages. In the grid below, 20 out of 100 squares are colored blue. 20% of the squares are blue.

Lesson Slides

The slider below shows some more examples of visualizing percentages using a grid of 100 squares. Open the slider in a new tab

What's in a Name?

"Per cent" comes from the Latin "per centum", meaning "by the hundred". The word "cent" appears in many contexts. In currencies, a hundredth of a US dollar is a cent. A hundredth of a Euro is also a cent. A hundred years is called a century and a hundred year anniversary is a centennial.

Other Types of Fractional Numbers

Percentages express a part of a whole. There are other ways of expressing parts of a whole: For example:
  • A fraction: 1/2
  • A decimal: 0.5
  • A negative exponent: 2−1
  • A percentage: 50%
  • A ratio: 1:2
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See Also

What is a percentage change? Converting percentages to fractions Converting percentages to decimals Understanding percentages ( interactive widget)