When you prepare for your aptitude test for the ASVAB, you will have to do a lot of math without a calculator. If you're comfortable using shortcuts, you'll learn how to save time, solve problems effectively, and ultimately score higher than someone as unprepared as you are.
You can learn some tricks by doing asvab math practice via https://www.andysasvabclass.com/ to convert decimal places to percentages.
Let's look at the long and correct solution first to make sure you get the material, then let's look at the abbreviations. The correct way to convert a decimal point to a percentage is to take your decimal point and see how many numbers are after the decimal point.
Using the 0.25 example, we have two numbers after the decimal point. We want to take the number in decimal, in this case 25. Divide by the number starting with 1 followed by as many zeros as you have.
Since 25 is two digits, we divide by 100 because it is 1 followed by 2 zeros. Our decimal number 0.25 is now 25 divided by 100.
To make a percentage out of this, you can look at the definition of the word "percent", which is for every 100. Since 0.25, so now 25, more than 100 is already divided by 100, here is our answer. 25 out of 100 means 25%.