How to solve math percentage problems

Calculator Use

Find a percentage or work out the percentage given numbers and percent values. Use percent formulas to figure out percentages and unknowns in equations. Add or subtract a percentage from a number or solve the equations.

How to Calculate Percentages

There are many formulas for percentage problems. You can think of the most basic as X/Y = P x 100. The formulas below are all mathematical variations of this formula.

Let's explore the three basic percentage problems. X and Y are numbers and P is the percentage:

Find P percent of X

Find what percent of X is Y

Find X if P percent of it is Y

Read on to learn more about how to figure percentages.

1. How to calculate percentage of a number. Use the percentage formula: P% * X = Y

Example: What is 10% of 150?

Convert the problem to an equation using the percentage formula: P% * X = Y

P is 10%, X is 150, so the equation is 10% * 150 = Y

Convert 10% to a decimal by removing the percent sign and dividing by 100: 10/100 = 0.10

Substitute 0.10 for 10% in the equation: 10% * 150 = Y becomes 0.10 * 150 = Y

Do the math: 0.10 * 150 = 15

Y = 15

So 10% of 150 is 15

Double check your answer with the original question: What is 10% of 150? Multiply 0.10 * 150 = 15

2. How to find what percent of X is Y. Use the percentage formula: Y/X = P%

Example: What percent of 60 is 12?

Convert the problem to an equation using the percentage formula: Y/X = P%

X is 60, Y is 12, so the equation is 12/60 = P%

Do the math: 12/60 = 0.20

Important! The result will always be in decimal form, not percentage form. You need to multiply the result by 100 to get the percentage.

Converting 0.20 to a percent: 0.20 * 100 = 20%

So 20% of 60 is 12.

Double check your answer with the original question: What percent of 60 is 12? 12/60 = 0.20, and multiplying by 100 to get percentage, 0.20 * 100 = 20%

3. How to find X if P percent of it is Y. Use the percentage formula Y/P% = X

Example: 25 is 20% of what number?

Convert the problem to an equation using the percentage formula: Y/P% = X

Y is 25, P% is 20, so the equation is 25/20% = X

Convert the percentage to a decimal by dividing by 100.

Converting 20% to a decimal: 20/100 = 0.20

Substitute 0.20 for 20% in the equation: 25/0.20 = X

Do the math: 25/0.20 = X

X = 125

So 25 is 20% of 125

Double check your answer with the original question: 25 is 20% of what number? 25/0.20 = 125

Remember: How to convert a percentage to a decimal

Remove the percentage sign and divide by 100

15.6% = 15.6/100 = 0.156

Remember: How to convert a decimal to a percentage

Multiply by 100 and add a percentage sign

0.876 = 0.876 * 100 = 87.6%

Step-by-step explanation:

to plot points   for x just start at the origin (middle) and go to the left however many times it say(if the number is a positive) if the number is a negative then go right however many times it says if it is 0 go nowhere

now keep you pencil there and go up however many times it says on y(if it is positive) if it is negative then go down however many times it says. if it says 0 go nowhere.

you have just plotted a point! now when you finish plotting all of them connect them with a ruler

plot each point as (-3, 7), (0,4), (3,1), (8,-4)   in the parenthesis on the left of the comma is x and the right is y.

7 ft 6 in means 7 1/2, because 6 in is 1/2 of a foot. 7 ft 8 in means 7 2/3 because 8 in is 2/3 of a foot. 23/3 = 7 2/3. 15/2 = 7 1/2.

23/3   *   15/2   = 57 1/2

step-by-step explanation: