To calculate 30% of $58 you would multiply 58 by 30 divided by 100. Because 30 and 100 are both
divisible by 10 you would multiply 58 by 3 and divide by 10.
58 × ^30 / 100 = 1,740/100 = 17.4 or $17.40
If you are not sure how to do the calculation, simplify the numbers to see how you do it. For instance,
let’s say you want to find 23% of 485 and you don’t know what you have to multiply or divide; try the
same calculation with easy numbers. How do you find 50% (½) of 10? You can see that you multiply 10
by ½ or you multiply by ^50 / 100 . Then you can apply this method to finding 23% of 485. You substitute 23
for 50 and 485 for 10.
You would get:
485 × ^23 / 100 = 111.55
You can check by estimation by saying that 23% is almost a quarter, and a quarter of 400 is 100.
Percentages are used in all areas of life: percentage discounts, percentage profits, statistics, sports
results and examination scores. We meet them every day.