What do you need to know:
- Percentages % are just fractions where 100 is always the denominator.
- Percentages can be easily represented as decimals. Simply move the decimal to the left 2 places.
- Useful to be able to find 1% of something in order to calculate problems.
Multiplication
- Multiplication is easy. Ignore the decimal and put it back after
Division
- Pretend the decimal does not exist and divide. Then put the decimal back after.
Then we need to put the decimal back. In this case, our original equation contained a number that had 1 decimal place to the right. Let’s put that back.
Increasing or decreasing by a percentage
Lantite can contain questions that ask you either to increase or decrease by a percent. For example, you could be asked something like…
“Mary favourite speaker costs $200 plus 10% GST. How much will Mary pay for her speaker?”
- with a calculator:
- without a calculator:
“Mary was excited to find out her favourite $200 speaker was on sale, with a discount of 10%. Assume Mary didn’t have to pay GST, how much will Mary pay for the speaker?”
- without a calculator
“Mary was told the $200 included 10% GST. What was to before GST cost?”
- with a calculator:
