A percentage is a way of expressing a number as a fraction of 100.
For example, 30% is the same thing as saying 30/100.
The best-known usage of percentages is in describing how large one quantity
is when compared with another quantity, such as “30% bigger”
or “20% greater”.
In mathematics, it is seen that if three numbers a, b and c are in proportion then: a = bc / 100. Thus for percent values we just need to know the value of ‘b’ and we can calculate the other two values: Percent= Value / Base x 100 .
To calculate the percentage of a number, multiply that number by the percentage value.
For example, to find 45% of 80: multiply 80 by 45%, which is 36. So 45% of 80 is 36.
Most calculators have a button that says “percent” or “%” for short. Pressing percent gives you your answer in percentage form instead of decimal format, so this works well if you already know the answer is a percentage and you just want to change it into an easier-to-understand format. If you don’t know what the answer should be in percentage form, though, it’s no problem; you can enter the original number and then your desired percentage (both in decimal form), and press the percent button to get the answer.
To calculate what 45% of 80 is, do this:
1) Put the original number (80) into calculator memory.
2) Type “45%” on calculator keypad.
3) Press equals (or whatever your calculator’s percent button is called).
The answer, 36, will show up on the screen.
Another example: what is 25% of 16?
1) Put 16 into memory.
2) Type “25%” on keypad.
3) Press equals (or similar button).