# How to calculate percentages?-Tips and Exercises

## How to calculate percentages

The percentages are applied daily and every day we see in the stores advertising with settlements of 20%, 30% up to 50% discount.

But how to quickly apply these discounts without complicating much. One of the fastest ways is with these simple examples. pixabay picturesMathematics knows no races or geographic boundaries. For mathematics, the cultural world is a country.-David Hilbert.

## How to calculate the final price?

Knowing how to develop the percentage technique is the solution. Percentages or percentages are easy to calculate, although at first glance it may seem otherwise.

It will not be necessary to learn a formula, it is possible to calculate through the rule of 3

## Example 1:

If you have 30 colors, of which 7 are red, what is the percentage of red colors that exist?

• 7 (RED COLORS)
• 30 EN THE TOTAL COLORS
• 100% IS THE TOTAL
• 30 COLORS = 100%
• 7 (RED) = x (this would be the equation to be solved)

## How is the operation calculated?

The following elements are multiplied:

### Step 1.

MULTIPLY 100 * 7 = 700

### Step 2.

DIVIDE 700/30 = 23.3333

23.3333% IS THE PERCENTAGE OF RED COLORS

## Another example is the following:

The number to which you are going to look for the percentage, you multiply it by the percentage that interests and you divide it by 100.

### Example How much is 25% of 40?

The number I am going to find the% is 40 and the percentage that interests is 25%.

## Step 2

The amount of the result you divide it by 100

80 X 30 = 2400
2400 ÷ 100 = 24

## A more Practical Method

When you do not have a calculator or a computer on hand, it is possible to calculate it in a mental way.

### Solution:

In this case, to make a very quick calculation, the first thing we must do is round the figure.

The ideal is to leave it at 4200 or 4300, this way it will be easier to do the calculation.

I will choose 4,300 because I prefer that I get money from the calculation that I will make

Then he eliminated the two zeros that exist in the figure to simplify a little more, but I must remember how many were to know how many I will add at the end.

## 4,300 ==> 43

Simplifying is the key, so to not complicate a lot I will also simplify my percentage in 2 parts: 2 and 0.5

43 * 2 = 86

43 * 0.5 = 21.5 or what would be the same:

Half of 43 is 21.5

now add: 86 + 21.5 = 87.5

Recall that at 4,300 we removed 2 zeros, now we just have to add them, removing one, which in this case is more about crossing the decimal point on the right: 875

These are several questions that were asked in the comments box, recently Facebook modified the plugin and were erased. Fortunately they were able to rescue to see if any of them could be among your doubts.

1. Question: 45 is that percent of 30?

Divides 100/30 and multiples by 45
100/30 = 3.333 x 45 = 149.9% almost 150%

2. Question: Hi, can you help me with this? The number 25 corresponds to 50% of a number. What percentage of that same number is the number 30?

Multiply 25 * 2 = 50, since you want to get 100%
100/50 = 2 x 30 = 60%

3.Question: I want to know how much is 30% of 240,000

Multiply 240 x 0.3 = 72 is 30% of 240

4.Question: As soon as an item for sale that costs 800 pesos and has a 30 percent discount?

Multiplies 800 * 0.3 = 240
Now that you have how much is 30% of 800
you only subtract: 800 – 240 = 560.

5.Question: As soon as an item for sale that costs 800 and has a 30 percent discount?

Multiplies 800 * 0.3 = 240
Now that you have how much is 30% of 800
you only subtract: 800 – 240 = 560.

6.Question: How is this problem solved? Which number increased by 14℅ results in 45.6

Divides 45.6 / 114, because in this case you do not want to take 100%, but 114%
45.6 / 114 = 0.4 now you multiply it by 100, to know what 100% would be
0.4 * 100 = 40 is the number that increased by 14% resulting in 45.6

7.Question: what is 18% of 7000

The simplest way to perform a calculation of this type is by multiplying the amount you want the percentage, in this case 7,000 for the amount you want to know the percentage, but divided by 100, in this case

18/100 =. 18
7,000 x .18 = 1260
18% of 7200 = 1260.

8.Question: How is this problem solved? Which number increased by 14℅ results in 45.6

Divides 45.6 / 114, because in this case you do not want to take 100%, but 114%
45.6 / 114 = 0.4 now you multiply it by 100, to know what 100% would be
0.4 * 100 = 40 is the number that increased by 14% resulting in 45.6

9.Question: If I charge 25,000 and they pay me 28,000 of what percentage was the increase?

First let’s take the difference that they increased, for which we subtract the original charge of the new one.
28,000 – 25,000 = 3,000
Now we apply the rule
25,000 is our 100%
We want to know what percentage corresponds to 3,000 of the total 25,000
3000 x 100 = 300,000
300,000 / 25,000 = 12
12% was the percentage that increased you.
You can corroborate it by multiplying 25,000 x 1.12 = 28,000

10.Question: Hello, ask, if a bank gives 18,79% for a fixed term to 30 days, as would the account for depositing \$ 150,000, thank you.

The simple and exact way is to multiply 150,000 x 0.1879 = 28.185.
If you want an approximate and mental calculation that percentage increases to 20%, eliminates zeros to simplify: 15 x 2 = 30, now returns the number of zeros that you removed minus one, in this case you removed 4, only returns 3. 30,000 would be sl when reviewing it you will notice that it is very close to the 28,185 that come out in the exact calculation.

11.Question: I’m going to sell something and I want 4,000,000 but the page charges me 11% of the total price per sale, that is, I can not only add 440,000, which is 11% of 4,000,000 because that 440,000 also have 11% what will be the exact amount for me to be left 4,000,000 removing 11% of the page mercadolibre

In this case, what you want to calculate is the sale price where the rules change, the formula is the following: Sale Price = Cost / (1 -% discount)
In your case it would look like this:
4,000,000 / (1 – 0.11) = 4,000,000 / .89 = 4,494,382.02

If you have any questions about how to calculate a percentage leave us a comment and we will gladly help .