First you have to change both of the mixed numbers to improper fractions. To do this you would multiply the denominator and the whole number then add the numerator.
1 2/3 = 5/3
-2 1/2 = -5/2
Find the least common denominator (LCM). Add the numerator, and keep the denominator the same.
The LCM for these two fractions would be 6 so to get to six you would multiply 5/3 by 2/2 and -5/2 by 3/3.
5/3 = 10/6
-5/2 = -15/6
Add the numerators (10 + -15 = -5), and keep the denominator the same (6). Therefore, the answer would be -5/6.
Explanation: Just multiply or use a calculator. The prime factorization is all the prime factors, meaning you can multiply all of them to get the original number.
