Fraction subtraction involves taking one fraction away from another. To subtract fractions, they must have the same denominator, which is the bottom number of the fraction. If the denominators are different, you first need to find a common denominator. Once the fractions have the same denominator, you subtract the numerators, which are the top numbers, and keep the denominator the same. For example, to subtract 1/4 from 3/4, you simply subtract the numerators: 3 - 1 = 2. The denominator remains 4, so the result is 2/4. This can be simplified to 1/2 by dividing both the numerator and denominator by 2.