Question 482117
You want to scale the numerator by the same amount that you scaled the denominator to produce an equivalent fraction. For example, if you want to do 3/4 + 1/6, the LCM of 4 and 6 is 12, and 3/4 = ?/12. Either by "scaling" or cross-multiplying we get ? = 9. Similarly, 1/6 = 2/12, and 3/4 + 1/6 = 9/12 + 2/12 = 11/12.