The calculation of the percentage is the order of the day, it is part of Mathematics that we cannot leave aside: knowing how to calculate, recognize, with or without a calculator because we constantly need it. When we go to a business and they tell us: this product has a 15% discount if you buy it in cash, if you do not pay on time the electricity bill will have a 5% surcharge, if you buy in installments the credit card applies a 3% monthly surcharge, etc., we see that we are constantly working with this simple calculation.
What do you need to get a percentage of a figure?
- Pencil and paper.
- Calculator.
Instructions to get a percentage of a number
- Let’s start by exemplifying percentages known to everyone even if we don’t know much about Mathematics:
- If we say that we ate half of a pizza we all know that half represents 50% of the total, pizza is the whole, the whole, 100%, therefore half a pizza is half, ½ of the total or 50%. As you will see we are not talking about numbers because nobody cares how big the pizza was or how much it cost, but we know that if they give me permission to eat 50% of it I will only be able to eat half.
- If we want to buy a gift that costs €60 for a friend and there are four of us to pay for it in equal parts, we must divide the number 60 by 4, that is, 60:4= 15 euros each. But what percentage of the total will we each pay? It’s simple: half of the total, that is, 50% equals €30, if we divide these €30 by two again, we will get €15, that is, 25%.
- It is as if we divided the pizza in half and then in half again: each quarter of a pizza represents 25% of the total.
- Let’s see another easy exercise: if my salary is 1000 euros, 50% of my salary is €500, 25% is €250, 10% is €100 (one tenth of 1000).
- Another easy problem: if a set of dishes is worth €50 and for cash payment they discount me 10%, first I must calculate 10% of 50 and then subtract it from 50, if you do the test you will see that you will pay for the set of dishes 45 €.
- Let’s see how to do it: 100% is the total, the whole, the price of the set of dishes, that is: €50. We propose a proportion: if 100% corresponds to €50, 10% will correspond to “x” €. This is written like this:
- Therefore the final price will be: €50 – €5 = €45
- If you want to do it faster and in a more mechanical way, you directly multiply the number from which you will get the percentage by the percentage and divide by one hundred:
- For example, if you want to get 15% of 3453, you multiply both numbers and divide it by 100:
- If we want to calculate 87% of 200, we consider:
- When we calculate a percentage greater than 100%, the number obtained will be greater than the original, for example, 200% of 4 will be 8, double four, let’s test if it is true and calculate 200% of 4:
- If you pay the electricity bill late, they charge you a 5.2% surcharge, how much will you pay if the original amount is €86 and you pay it three days after it expires?
- We calculate 5.2% of the original amount, and then we will add the surcharge to it, thus obtaining the total amount to be paid due to the delay.
Tips to get a percentage of a figure
- Managing mathematical concepts well, such as percentage calculation, is a tool for daily use that facilitates your economy and should not be missing.
- The simple rule of three, proportions are one of the methods of calculating percentages.
- Ask yourself simple problems to get used to using the calculator quickly.
- Calculators also calculate percentages directly for you, but it’s good to know what the procedure is in case you don’t have one handy.