Percentage means out of a hundred. To find a percentage, the original quantity is divided up into 100 parts. It is a fraction waiting to happen. A precentage value is shown with a symbol %.
38% is equivalent to `frac(38)(100)`.
Percentages are used to compare values: for example, you might score 45/60 for a maths test, and 63/75 for an English test. Using a percentage marks both scores out of 100: for maths the score is 75%, and for English it is 84%.
1. The atmosphere of the earth consists of 21% oxygen. Which would be the nearest value as a fraction: `frac(1)(4)`, `frac(1)(2)` or `frac(3)(4)`?
21% is equivalent to `frac(21)(100)`.
`frac(1)(4)` is equivalent to `frac(25)(100)`, so this is the nearest value.
2. A quarter of the pencils in a box of 100 pencils are broken. What percentage is this?
A quarter is 25 out of 100. As the value is out of 100, it is 25%