Change a decimal to a fraction by first identifying the number that is the furthest to the right of the decimal point. For example, .4 has one number (4) to the right of the decimal. If the decimal is .45, the 5 is the furthest to the right of the decimal.
Identify the place value of the number that is the furthest to the right of the decimal. In decimals, the first number to the right of the decimal is in the tenths place, the next is in the hundredths place and so forth. Therefore, if the decimal is .4, the number the furthest to the right (4) is in the tenths place. If the decimal is .45, the number the furthest to the right of the decimal (the 5) is in the hundredths place.
Place the numbers to the right of the decimal over the place value of the number the furthest to the right of the decimal. For example, if the decimal is .4, your fraction would be 4/10, since the 4 is in the tenths place. If your decimal is .45, your fraction would be 45/100, since the 5 is in the hundredths place.
An easy way to do this is to ask "How many digits are there to the right of the decimal?" and then place that many zeros after the 1 on the bottom of the fraction. For example, if the decimal is .45, there are two digits to the right of the decimal. Your fraction, 45/100, has two zeros in the bottom number.
Place any numbers before the decimal point to the left of the fraction as a whole number. The numbers to the left of, or before, the decimal point always represent whole numbers. Therefore, if your decimal is 3.45, your fraction would be 3 45/100, or 3 and 45/100.