Fractions can take two forms, and whichever form you use, you can use your calculator or your notepad to find two-thirds of a number. For example, you can write two-thirds in fractional form – 2/3 – or as a decimal – 0.667 – and either way, you calculate two-thirds of a number by multiplying by that number. The operations are equivalent, although if you’re using your notepad, you may prefer to use the fractional form.

By Calculator

Step 1

Type in two divided by three and press the equals sign on your calculator. You should receive a decimal similar to 0.666 repeating.

Step 2

Press the multiplication sign and type in the number of interest. For example, if you are finding two-thirds of 100, after you press multiplication sign type in “100.” Then press the equals sign.

Step 3

Interpret your result. If you have 66.66 repeating, then you may wish to round this to the tenths place of 66.7. Thus, two-thirds of 100 is approximately 66.7.

By Hand

Step 1

Divide the number of interest by 3. If you are finding two-thirds of 60, then first divide 60 by 3. You will get the number 20 as your result.

Step 2

Round your result to the tenths place. In some cases, you may get a repeating decimal and it may be easier to use a smaller approximation. For instance, if you divide 250 by 3 you get 83.333 repeating. You may want to use 83.3 as your result instead of the entire decimal.

Step 3

Multiply the result by 2. If you have 20 as your result, then 20 times two is 40. Therefore, two-thirds of 60 is 40. By the same token, two-thirds of 250 is 83.333 x 2 = 166.667.

TL;DR (Too Long; Didn’t Read)

You can also multiply by two first and then divide your result by three, when calculating two-thirds by hand.