How to find the percentage of two numbers? - Cookies! 🍪

A percentage is also a way to express the relation between two numbers as a fraction of 100. In other words, the percentage tells us how one number relates to another. If we know that number A is 25% of number B , we know that A to B is like 25 is to 100, or, after one more transformation, like 1 to 4, i.e., A is four times smaller than B . This is what the percentage calculator teaches; what is a percentage and how to find a percentage of two numbers. It is essential and practical knowledge. Why? Let's say that B represents the mass of a human body or the mass of some air. Then, by denoting A as a mass of water, we can find out what is the total body water percentage or relative humidity (used to calculate the dew point of air).

How to find a percentage of something? It's easiest to explain what is the percentage with cookies. It is surprising how often cookies save the day, right? Say we have a big drawer with 100 compartments (a 10 x 10 grid). Every compartment is one hundredth or 1% of the whole drawer. We then fill this drawer with cookies in a way that gives us exactly the same number of cookies in each compartment.

At first, let's start with the most straightforward example with 100 cookies. How to get the percentage of several, let's say, five cookies? It's easy: every compartment gets exactly one cookie. So one percent of 100 is one cookie, and five percent is five cookies.

Let's go with something a bit harder and four times more delicious: 400 cookies! We're dividing them evenly, and every compartment gets four cookies. Cookies look smaller, but in our imagination, they are the same, just the drawer is much bigger! One percent of 400 is 4. How about 15 percent? It's 15 compartments times four cookies - 60 cookies. Our tummies start to ache a little, but it has never stopped us from eating more cookies!

Now, something even harder - 250 cookies. Oh-oh, we divided up the first 200 cookies, placing two in every compartment. Now we are left with 50 cookies that need to be spread evenly, hmmm, it's half a cookie in every box. How to calculate the percentage? You are right - this time, 1 percent of the total number of 250 cookies is 2.5. How many do we have in 15 boxes? 2.5 * 15 is 37.5.

So what is percentage good for? As we wrote earlier, a percentage is a way to express a ratio. Say you are taking a graded exam. If we told you that you got 123 points, it really would not tell you anything. 123 out of what? Now, if we told you that you got 82%, this figure is more understandable information. Even if we told you, you got 123 out of 150; it's harder to feel how well you did. A week earlier, there was another exam, and you scored 195 of 250, or 78%. While it's hard to compare 128 of 150 to 195 of 250, it's easy to tell that 82% score is better than 78%. Isn't the percent sign helpful? After all, it's the percentage that counts!

What about decimal fractions and percentages? Percentages can easily be converted to decimals. Just divide the percentage by 100, and you are set. 15% is the same as 0.15. So as we have shown before, 0.15 of 250 cookies is thirty-seven and a half.

Percentages are sometimes better at expressing various quantities than decimal fractions in chemistry or physics. For example, it is much convenient to say that percentage concentration of a specific substance is 15.7% than that there are 18.66 grams of substance in 118.66 grams of solution (like in an example in percentage concentration calculator). Another example is efficiency (or its special case - Carnot efficiency). Is it better to say that a car engine works with an efficiency of 20% or that it produces an energy output of 0.2 kWh from the input energy of 1 kWh? What do you think? We are sure that you're already well aware that knowing how to get a percentage of a number is a valuable ability.