Calculating a percentage is a basic skill that everyone must know. Using basic math operations like division➗ and multiplication✖️, we can learn how to calculate percentages.
Percentages are important because -academic performance, increase in the prices of food and fuel, how much interest we get on our savings in a bank account, discounts on products, etc. all these things are expressed in percentage.
What is a Percentage? %
A percent is a part of something that is complete or whole. A percent is expressed in terms of fraction of 100. The symbol used to express the percent is “%”. The whole is expressed as 100 percent (100%).
If we cut a pizza into two equal halves then we say it is now 50–50, meaning the whole pizza(💯), which is 100 percent, is now divided into two equal halves meaning one part/piece is 50 percent of that whole pizza.
Formula: to calculate Percent-
In the above example, the pizza is the whole and that half of the pizza is a part of the pizza.
- So, the formula of the percentage is as follows – 👇
Percentage = [ part ➗ whole ] ✖️ 100
Now, let’s try a few examples –
- A student scored 90 marks out of 120. Then calculate the percentage.
- the formula is Percentage = [ part ➗ whole ] ✖️ 100
- here, part = 90 and whole= 120
- Percentage = [90➗120] ✖️ 100 = 0.75 X 100 = 75%
- The student scored 75% in that particular subject
- You got Rs.80 discount on a T-shirt of Rs.400. Express the discount in terms of percentage.
- here, part= 80 & whole=400
- Percentage= [80➗400] ✖️ 100 = 0.2 X 100 = 20%
- the discount on the T-shirt is 20%.
- The price of a car was Rs.10,00,000 a year ago and now the same car is worth Rs.11,50,000. Then calculate the percentage of the price hike.
- here, part = 11,50,000 ➖10,00,000 = 1,50,000. And whole = 10,00,000.
- Percentage= [150000➗1000000] ✖️ 100 = 0.15 X 100 = 15%
- So, the hike in the price of the car is 15%
Reverse calculation examples –
When the percentage is given, but we need to find out the part or the whole.
- Like, What is the 30 % of Rs.500 ?
- Here, we have percentage = 30 %, whole= 500 and asked to find out the part.
- Percentage = [ part ➗ whole ] ✖️ 100
- therefore, Part = [whole✖️ percent] ➗ 100
- Part = [500 X 30] ➗ 100 = 150
- Answer is Rs.150 is the 30% of Rs.500.
- When a discount of 60% is given on a T-shirt, the customer bought it with discount at Rs.200. Then what is the original price of the T-shirt without the discount?
- Here, logically, we can see that Rs.200 is the 40% of the whole. So, we need to calculate the 60% of the whole.
- then the question is Rs.200 is the 40% of what?
- to calculate this, we have the following formula 👇
- Whole = [part X 100] ➗percent
- Whole = [200 X 100]➗40 = 500.
- the answer is Rs.500.
- We can check this by these values in our original formula.
Visit here to use the percentage calculator ➡️ calculator
Simple way to calculate a percent
To understand this trick, we should know about the decimals.
- If I write 100 then
- it also means 100.000
- it also means 100.000000
- If it is written 4325.75 then
- it means 0.75 is added to 4325.00
- By multiplication with 10, the decimal point will move one place towards the right side.
- 4325.75 X 10 = 43257.5
- And by dividing the number by 10, the decimal point will move towards the left side.
- 4325.75 ➗ 10 = 432.575
Using the above concept, we can calculate any percentage easily
- What is 10 percent of 200 ?
- If we divide any number by 10 then we get the 10% of that number.
- So, 10% of 200 is 20.
- And if we divide the 10% of any number by 10, we get the 1% of that number.
- So, 1% of 200 is 20 ➗10 = 2. The 1% of 200 is 2.
- What is 10 percent of 7517 ? (7517 can be written as 7517.000)
- 7517 ➗ 10 = 751.7
- The 10% of 7517 is 751.7
- And if we divide the 10% of any number by 10, we get the 1% of that number.
- The 1% of 7517 is 75.17 (751.7)
Using this simple concept, we can calculate the percentage very easily.
- To calculate 10% of any number, we need to shift the decimal point one place to the left side.
- To calculate 1% of any number, we need to shift the decimal point two places to the left side.
- What is the 10 percent of 4255.62 ?
- To calculate 10% of any number, we need to shift the decimal point one place to the left side.
- 10% of 4255.62 is 425.562
- and 1% of 4255.62 is 42.5562
Once we calculate the 1% of any number, then we can easily calculate the asked percentage of that number.
- What is 37% of 7560 ?
- the 1% of 7560 is 75.60
- So, 37% = 37 ✖️ 75.60 = 2797.2
- What is 45% of 1000 ?
- the 1% of 1000 is 10
- so, 45% of 1000 = 45✖️ 10 = 450
This trick is more useful for complete numbers, though it works for any number with decimals and fractions.