Write down a fraction. For example, you might use 50/60.
Look for the largest factor that can be divided evenly into both the numerator and the denominator. The factors of 50 are 1, 2, 5, 10, 25 and 50. For 60, the factors are 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30 and 60. In this example, 10 is the largest number that is a factor of both 50 and 60.
Divide the numerator and denominator by the greatest common factor. So 10 divides into the numerator, 50, five times, and into the denominator, 60, six times. In this case, you would get the simplified fraction 5/6.