On the GED math test you will need to be able to easily change percents to decimals and vice versa in order to work through all of the questions successfully.
Changing Percents to Decimals
Since percents are just ways to represent parts of hundreds without a decimal, all you need to do is move a decimal two points to the left. For example:
So .11 is 11% changed to a decimal. Remember that 11% and .11 equal the same value.
Not every time you change a percent to a decimal will the decimal be a number with no value to the left of the decimal and two digits to the right of the decimal as it was .11 above. For example if you change a number less than one percent to a decimal there will be three digits to the right of the decimal. For example what decimal is equal to one half of a percent (0.5%)?
Another situation where a percent converted to a decimal won’t result in no digits to the left of the decimal and two to the right will be when you have a percent greater than 100%. For example, let’s say last year you made $30,000 and this year you will make $45,000. The way to represent the amount you will make this year compared to the amount you made last year by percent is 150% since 45 is 1.5 times 30.
1.5 = 150%.
Converting Decimals to Percents
Just as you moved the decimal two spaces to the left when going from percent to decimal, when you convert from decimal to percent, just move the decimal two places to the right and add a percent sign.
You might also need to convert a decimal with more than two digits to the right of the decimal point, or a decimal with a value to the left of the decimal point:
The video below is an example of the kind of problem you might see on the test where you need to convert a percent to a decimal to solve the problem quickly and accurately.