Percentages

What is a percentage?


A percentage is simply a way of representing a number, as a fraction of 100. Its really just a way of describing a proportion, or a share of something.

So, if a bag contains 50 red balls and 50 blue balls then 50% of the balls in the bag are red and 50% of the balls are blue. This is because, there are 50 out of 100 balls which are red - so its described as 50%. This is another way of saying half the balls are red - because 50/100 is equal to 0.5.

Similarly, if the bag contained 100 balls but only 25 balls were red then we would say that 25% of balls in the bag were red. This would be the same as saying that a quarter of the balls in the bag were red - and we work this out because 25 out of 100 is the same as 25/100, which simplifies to 1/4 or 0.25.


Lets try some examples ...


If we were to write 90% as a fraction, in it's simplest form we'd say ...


If we were to write 25% as a fraction, in it's simplest form we'd say ...


If we were to write 9 out of 12 as a percentage, how would we do it?





But, if we wanted to convert numbers from percentages to decimals, how would we do it?





If we wanted to convert 34% to a decimal, how would we do it?





Similarly, if we wanted to convert 87.2% to a decimal, how would we do it?