A Simple Guide to Using Your Calculator

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An easy-to-follow guide to using your calculator like a pro

Co-authored by David Jia and Travis Boylls

Last Updated: August 26, 2026 Fact Checked

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• Learning Basic Functions
|
• Using the Memory Function
|
• Using Decimals and Percentages
|
• Using Fractions
|
• Finding Exponents and Squares
|
• Using Scientific Functions
|
• Video
|
• Q&A
|
• Tips

|Show more |Show less

Using a calculator to do basic math functions isn’t too difficult. However, it can be a little more confusing when you need to do fractions, percentages, or exponents, especially if you don’t have a scientific calculator. Still, it’s pretty easy to get the hang of it. Once you learn what the buttons do and how to use them for different calculations, you'll be more than comfortable using your calculator whenever you need it—inside or outside of school! This wikiHow article teaches you how to use a calculator to do various functions.

Using a Calculator

Use the plus (+), minus (-), multiply (x or *), and divide (÷ or /) buttons to do basic math functions. Press the equals (=) button to get an answer to your calculation. Use the dot button (.) to add decimals. You can also use the percent button (%) to turn a number into a percent.

Steps

Method 1

Method 1 of 6:

Learning Basic Functions

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1. 
   1
   Press C or AC to clear your calculator. When you power on a calculator, it may have the previous calculation displayed on screen. You can clear your calculator by pressing the “C” button. This will return the number on the screen to 0, and you will be ready to start a new calculation.

   • Most calculators have a “C” button to clear the latest calculation.
     • They may also have an “All Clear (AC)” button. This button is used to wipe everything, including the memory keys.
     • The CE ("Clear Entry") button will clear the most recent entry. For example, if you just typed a "2" by mistake, press "CE" to delete just the 2.
   • If you hit "+," "-," "x," or "/" after a number and then try to start a new equation without first hitting "Clear," it will become a part of the current equation. Always hit "Clear" when you need to restart from the middle of a calculation.
   • If you don’t see a number or a “0” on the screen, make sure your calculator is powered on. If it is solar powered, make sure it has plenty of light.
2. 
   2
   Add numbers with the + key. Hit the "+" button between any two numbers to add them. For example, to add 5 to 10, press "5," "+," then "1" and "0."

   • Add additional numbers to a series. For example, press "+" and "5" to add to the sum of "5 + 10." When you need the final answer, press the "=" button to get the sum of "20."
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3. 
   3
   Subtract numbers with the - key. Press the "-" button between any two numbers to subtract the second from the first. For example, hit "7," "-," and then "5" to subtract 5 from 7 and hit "=" to get an answer of "2."

   • Subtract additional numbers from a series. For example, press "-" and "2" to subtract from the sum of "2 – 7" and then press "=" to get a final answer of "0."
   • Try subtracting numbers after adding them.
4. 
   4
   Multiply numbers using the x or * key. For example, to multiply 6 by 5, press "6," "x," "5," and then "=." The final answer will read "30."

   • Physical calculators often use "x" as a multiplication key, while computer calculators typically use "*".
   • Multiply in a series by pressing "x" or "*" followed by a number. For example, if your calculator says "6 x 5," press "x," "2," and then "=" to get a final answer of "60."
5. 
   5
   Divide numbers with the ÷ or / key. For example, to divide 2 by 1, press "2," "÷," and "1" and then "=."

   • You can also use the Divide function to create decimals out of fractions. To change the fraction 4/5 to a decimal, press "4," "/," "5," and then "=."
   • If you're using a physical calculator, the division key is likely "÷." For computer calculators, the division key is probably "/."
   • Divide in a series by pressing "÷" or "/" followed by a number. For example, if your calculator says "2 ÷ 1," hit "÷," "2," and then "=" to get a final answer of "1."
6. 
   6
   Press the = button to get the answer to an equation. After inputting your equation's numbers and operations, such as addition or subtraction, hit "=" to get the final answer. For example, press "10," "+," "10," and then "=" to get a final answer of "20."

   • Remember that you can change your equation without clearing everything after pressing "=" only with ←/→ key, so always double-check your numbers first!
7. 
   7
   Press ← Backspace, Delete, Del, ←, or CE, to clear the last number. If you want to clear the last number on your screen without wiping the whole equation away, hit the "Backspace" or "Delete" button. For example, say you hit "4," "x," "2," but wanted to press "4," "x," "3." Press "Delete" to remove the "2" and then press "3" and you should see "4 x 3" on the display.

   • The "CE" button stands for "Clear Entry."
   • If you press "Clear" instead of "Backspace" or "Delete," your equation will reset to "0."
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Method 2

Method 2 of 6:

Using the Memory Function

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1. 
   1
   Press M+ to add a number to memory. This can be a number you enter into the calculator, or it could be the result of a calculation. This stores the number in the calculator's memory so that it can be recalled for use in another calculation.

   • When you add a number to memory, you will usually see an “M” on the screen. This indicates there is a number in memory.
2. 
   2
   Press M- to add a number to memory as a negative integer. When you use the “M-” button, this will add the number as a negative. You can use this to subtract the number from another number or enter it as a negative number.
3. 
   3
   Press the MR to recall a number from memory. Pressing the MR button will enter the number from memory into the calculator. You can add it as part of an equation, or you can just press the button to see what is in memory.

   • For example, if you want to multiply the number memory by 2, you would press “2 x MR =” to get your answer.
   • Some calculators may have a key M and a diamond symbol instead. This is the Memory Recall key.
4. 
   4
   Press MC to clear the memory. If you want to clear whatever number is in the memory, press “MC” to do so. This deletes the number from memory.

   • Some calculators have a single button that recalls and clears the memory. If you see a button that says “MRC”, press the button once to recall the number from memory. Press the button again to clear the memory.
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Method 3

Method 3 of 6:

Using Decimals and Percentages

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1. 
   1
   Press the . button to create decimal numbers. Start by pressing the number before the decimal, hitting the "." button, pressing the number after the decimal, and then hitting the "=" button. For example, to create "50.6", hit "5", "0", ".", and "6”.

   • If you're adding, subtracting, multiplying, or dividing after you create your decimal number, you don't have to hit "=".
   • Use the "+," "-," "x," and "÷" buttons to add, subtract, multiply, and divide decimals, respectively.
2. 
   2
   Turn numbers into percentages with the % button. Hit the "%" button to divide the number on your screen by 100, which turns it into a percentage. If your calculator doesn’t have a “%” key, you can simply divide by 100. For example, if you want to know what 7 percent of 20 is, start by hitting "7" followed by "%" to get 0.07. Now, hit "x" then "20" to multiply the percentage—0.07—by 20, which gives you your answer: "1.4."

   • To turn a percentage back into a number, multiply it by 100. In the last example, you hit "7" and "%" to get 0.07. Now, hit "x" and then "100" to multiply it by 100 and get the original number: "7".
   • You can also simply multiply the number by 0.x, replacing x with the desired percentage. For instance, to know what 15 percent of 40 is, multiply 40 by 0.15.
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Method 4

Method 4 of 6:

Using Fractions

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1. 1
   Group integers and calculations together with the bracket ((, )) keys. If you live in the U.S., brackets are called parentheses. The calculations inside the brackets will be performed first. For example, if you enter “(2+9)x(3+5)=,” “2+9” and “3+5” will be calculated before they are multiplied, instead of “9x3” being multiplied first.
2. 
   2
   Create fractions using the bracket buttons and the division key. Always start with a left bracket, "(" followed by the numerator, which is the number above the line in a fraction. Now, press the "÷" or "/" key and then the denominator (the number on the bottom). Then enter the “)” bracket. For example, "5/6" is made by hitting "(," "5," "/," "6," and then ")."

   • Use the "+," "-," "x," and "÷" buttons to add, subtract, multiply, and divide fractions, respectively. Just don't forget to put brackets around each fraction or the calculation will be off!
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Method 5

Method 5 of 6:

Finding Exponents and Squares

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1. 
   1
   Create the inverse of a number by hitting 1/x or x-1 key. This is also known as the inverse key. This gives you the reciprocal of any number, which is equal to 1 divided by the number. For example, the reciprocal of 2—which in fraction form is 2/1—is 1/2. This means that you can hit "2" and then "1/x" to give you an answer of 1/2 (0.5 in decimal form).

   • This button is only on scientific calculators. If you don’t have a scientific calculator, you can find the inverse of a number by entering “1” and then dividing it by the number you want to find the inverse of. For example, you can find the inverse of 5 by entering “1 / 5 =”.
   • A number multiplied by its reciprocal is always equal to 1.
2. 
   2
   Find the square of a number by pressing X2 key. Enter the number you want to find the square of and then hit the Square key. If you don’t have a scientific calculator, you can find the square by multiplying a number by itself. For example, to find the square of 6, you would enter “6 x 6 =”.
3. 
   3
   Press the √ to find the square root of a number. The square root of a number is the number you need to multiply by itself to get the current number. For example, the square root of 4 is 2. So if you press 4, followed by the square root button, you’ll get 2.

   • If you don’t have a scientific calculator, sorry, you’ll have to use a different math trick to find the square root of a number.
4. 
   4
   Calculate the exponent of a number by pressing ^, x^y, or xy key. The exponent (or power) of a number refers to how many times it's multiplied by itself. For example, the 2 in x² (x squared) is an exponent--you square a number by multiplying itself by itself two times (x * x). With the exponent key, the first number (x) is the main number you're multiplying by itself, while the second number (y) is the exponent, or the number of times you're multiplying x together.

   • For example, "3^6" is 3 to the power of 6, which is equal to "3 x 3 x 3 x 3 x 3 x 3." This can be calculated with the power or exponent button using this order of operations: press "3," press "x^y," press "6," and press "=." The final answer is "729."
   • If you don’t have a scientific calculator, you’ll need to multiply the number by itself the number of times of the “to the power of” number. For example, to find "3^6" you would multiply, "3 x 3 x 3 x 3 x 3 x 3."
   • Any number (x) to the power of 2 is called x squared, while any number (x) to the power of 3 is called x cubed.
   • The "^" key is most often found on graphing calculators, while the "x^y" and "yX" keys are found on scientific calculators.
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Method 6

Method 6 of 6:

Using Scientific Functions

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1. 
   1
   Calculate scientific notation using the EE or EXP button. Scientific notation is a method of expressing large numbers—such as 0.0000000057—in a simpler way. In this case, the scientific notation is 5.7 x 10-9. To turn a number into scientific notation, enter the digit number (5.7) and then hit "EXP." Now, press the exponent number (9), the "-" key, and then hit "=."

   • Don't hit the multiply (x) button after hitting "EE" or "EXP."
   • Use the "+/-" button to change the sign of the exponent number.
2. 
   2
   Use your calculator for trigonometry with the sin, cos, and tan buttons. To find the sine, cosine, or tangent of an angle, start by entering the angle value in degrees. Now, press the "sin," "cos," or "tan" button to get the sine, cosine, or tangent, respectively.

   • If you don’t have a scientific calculator, you can find the sine of a right angle by dividing the opposite side (O) by the hypotenuse (H). To find the cosine, divide the adjacent side (A) by the hypotenuse (H). To find the tangent, divide the opposite side (O) by the adjacent side (A).
     • Sine = O/H, Cos = A/H, Tan = O/A.
   • To convert the sine into an angle, press the sine value and then hit "sin-1" or "arcsin."
   • If you want to turn an angle's cosine or tangent into the angle value, press the cosine or tangent value and then press "cos-1" or "arccos."
   • If your calculator doesn't have "arcsin," "sin-1," "arccos," or "cos-1" buttons, hit the "function" or "shift" key and then press the standard "sin" or "cos" button to turn their values into angles.
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• Question

  How to add fractions on calculator?

  

  Joonhyuk Choi

  Community Answer

  Calculators can't show the answer in fraction form, but you will get the answer in decimal form if you add it as: (number/number)+(number/number).

  Thanks! We're glad this was helpful.
  Thank you for your feedback.
  If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow

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• Question

  How do I display the equal sign on a calculator?

  

  Community Answer

  Calculators will never display the equal sign. The equal sign can be understood as the "Enter" sign of a calculator actually performing the intended operation.

  Thanks! We're glad this was helpful.
  Thank you for your feedback.
  If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow

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• Question

  How do you calculate a negative exponent?

  

  Community Answer

  See Calculate Negative Exponents.

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  Thank you for your feedback.
  If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow

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• If you have a graphing calculator, you can use it to perform more complex operations, like graphing a function or solving an equation. Check the manual that came with your calculator for detailed instructions.
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