Question

Carrie found the difference 11/12 -- 2/3. she said * i found a common denominator 12,then subtracted the numerators to get 9/12* is carrie correct? Explain why she is or not correct.

Answer 1

She isn't correct because after you find the common denominator, the numerator needs to be changed as well, so when she multiplied the denominator of 2/3 by 4 to get 12, she also had to multiply the 2 by 4, to get 8/12, and then subtracted, because otherwise, the new fraction isn't equivalent to the original fraction.