Write out the fraction and learn the relationship of the digits. A fraction is way to show a ratio of two numbers as well as showing parts of a larger group.
For example, the fraction 3/4 is the ratio of 3 to 4. It also symbolizes 3 parts out of every 4. For example a dollar contains 100 cents. When calculating 3/4 of a dollar, divide the dollar into 4 equal parts, so each part is 25 cents. Three of those quarters is 75 cents. This means that 3/4 of a dollar is 75 cents. Mathematically, you are taking the 100 cents and dividing by the number on the bottom of the fraction, the 4. That answer is then multiplied by the top number, the 3, to get the answer 75 cents. Always remember to divide by the bottom and then multiply by the top.
Write the fraction as a decimal. Divide the bottom number of the fraction into the top number to get the decimal equivalent to the fraction. For the fraction 2/5, for example, divide 5 into 2 to get .4 -- the equal amount written as a decimal.
For proper fractions, those less than one, the division is always a larger number into a smaller one. This means that when dividing, you place a decimal point to the right of the smaller number and write a zero to the right of it to do the division. In this case, 5 is divided into 2.0 to get .4 as the answer. If the fraction is a mixed number, or an improper fraction, then the answer is greater than 1. For example 2 2/5 is equal to the decimal 2.4, with the whole number going to the left of the decimal and then dividing the fraction out. The improper fraction 15/4, when divided out (4 divided into 15) gives the decimal equivalent 3.75 (4 goes into 15 three time with 3 left over that 4 goes into .75 time). Use a paper and pencil to write out the division and learn the process. A calculator can only help if you understand the mathematical process.
Change the decimal to a percentage. Percentages show parts out of 100, so 30 percent means 30 parts out of every 100. When talking about 30 percent of an apple, for example, it means if the apple were divided into 100 parts then 30 percent is 30 of those 100 parts. To change a decimal to a percentage, move the decimal point over two places to the right. In the example from the previous steps, .75 equals 75 percent and .4 equals 40 percent. When there are not two or more digits to the right of the decimal to move it over, then zeros are placed on the right side of the number. The number 3.75, for example, is equal to 375%, so the fraction 15/4 is equal to 375%.
Watch for repeating decimals. Some fractions, when divided out give never-ending answers. For example, 1/3. When dividing 3 into 1, the answer is a never-ending row of 3's or .3333 continuing forever. The answer is to carry the repeating number out as far as needed and round to the nearest number. In this case, to the nearest hundredth place gives .33, which is equal to 33 percent. The fraction 2/3 gives the repeating decimal .6666. When divided out and rounded it becomes .67 or 67 percent.