Obtain two fractions with the same denominator. For this example, let the fractions be 7/10 and 9/10.
Square one of the denominators. In this example, 10 squared is 100.
Multiply one numerator by the other. In this example, 7 multiplied by 9 equals 63.
Write the product of the numerators over the squared denominator for the answer. For this example, writing 63 over 100 results in 63/100.
Simplify the fraction if it needs it. Simplifying a fraction means to reduce it to its lowest terms possible by canceling out common factors other than the number 1. For example, in the fraction 2/8, the numerator and denominator both have 2 as factors, where 2/8 equals 2*1/2*4. Canceling out 2 from both the numerator and denominator results in 1/4. Concluding the example, 63 and 100 have no common factors larger than 1, so the fraction cannot be simplified. The final fraction is 63/100.