9/12 is already a fraction. However, it is not but into lowest terms, also known as simplest form. If both the numerator and denominator are visible by a number greater than 1, you are able to reduce the fraction. In this case, 9 and 12 are both divisible by the number 3.

9 / 3 = 3

12 / 3 = 4

The numerator simplifies to 3, and the denominator simplifies to 4. The fraction 9/12 is able to be reduced to 3/4.