Percentages are used for a variety of things, usually when we want to describe how much of something there is.
For example, perhaps you only want $$50% of the juice in your cup, when the car dashboard says that the fuel tank is only $$20% full or when your phone battery has $$78% life left.
However, $$50% of the water in a $$100 L swimming pool is obviously very different to $$50% of the $$2 L milk in your fridge. Let's take a look at how we can figure out how much there ACTUALLY is when we hear about percentages.
We already know how to find a fraction of a quantity through multiplication. For example, we know to find $$23 of $$60 all we do is multiply the two numbers together, so $$23×60=40 is our answer. We can do the same with percentages as we know how to turn them into fractions with $$100 as the denominator.
For example, we want to find what $$71% of $$526 is, so let's multiply them together.
$$71%×526 can be rewritten as
$$71100×526=71×526100.
Using a calculator we know this equals $$37346100, which is $$1867350 in simplified form.
Sometimes such large messy improper fractions are easier to understand as mixed numbers, so in this case we can evaluate $$1867350 as $$3732350.
Can you see we can easily estimate this to $$37312? So much simpler!
Evaluate $$28% of $$5000.
Evaluate $$51.3% of $$240
Express your answer as a decimal.
Lisa scored $$70% on her Maths exam, which was marked out of $$140. What was Lisa's actual mark out of $$140?