In mathematics, a percentage is a ratio presented as a fraction in terms of 100. It is often expressed using the percentage sign, “%,” or sometimes as “pct.” A percentage is a dimensionless number (pure number) with no measurement unit. Finding the percentage of two numbers is easy and only requires simple math. If you need to know how to calculate the percentages of two numbers, follow these steps.
1) Determine the whole:
The first step in finding a percentage is to determine the whole that you measure against. In almost all cases, this will simply be 100%, which represents the entirety of the field being considered. You can express this as either 100 or 1.00.
2) Convert your decimal fractions to percentages:
You will almost certainly need to convert decimal fractions into percentages. This process is incredibly easy; multiply your decimal by 100%. For example, if you wanted to know what 20% of 64 is, you would first convert 20% into a decimal by moving the decimal point two places to the left. This gives you 0.20. You would then multiply 0.20 by 64 to get 12.8 (rounded up from 12.8333…).
3) Find the desired value:
The last step is simply solving for your desired value—in this instance, finding out what 20% of 64 is—using basic algebraic principles. In other words, set up an equation with what you know and solve for what you don’t know! In this problem, we know that 20% = 0.20 = 12.8/64; thus, x = 12.8/0.20 = 64*.20 = 12.8 (where * represents multiplication).
4) Check your work:
As with any mathematics problem, it is essential that you check your work! To make sure that our answer is correct, we can plug it back into our original equation to see if it checks out: 20% = 0.20 = 12.8/64; 64*0.20 = 12.8/0 — everything on either side of the equals sign cancels out except for 12.8/12.8 on the right-hand side, which equals 1 or 100%. As expected!
What are some common mistakes to avoid when calculating percentages?
1) One common mistake people make when calculating percentages is failing to convert their fractions into decimals. Remember, a percentage is a fraction of 100, so any fraction can be easily converted into a percentage by multiplying it by 100%.
2) Another common mistake is forgetting to move the decimal point two places to the left when converting a percentage into a decimal. This is an easy mistake, but it can cause significant problems in your calculations!
3) Always make sure to check your work by plugging your answer back into the original equation. This simple step can save you a lot of headaches down the line!
4) Last but not least, avoid rounding your numbers too early in the process. Although it may be tempting to round up or down to make the math more accessible, this can introduce errors in your calculations. Instead, try to work with exact numbers for as long as possible before rounding.
Calculating percentages may seem daunting at first, but once you get the hang of it, it’s a breeze! And remember, always check your work!