Brad built 1/4 of a model airplane on monday and 2/3 of it on tuesday. he finished building the airplane on wednesday. what fraction of the airplane did he build on wednesday?

Teh answer is 1/12. 1/4+ 2/3 is 11/12. First, you need to find the common denominator of 4 and 3, and that is 12.Then, you multiply 1*3 because 4*3 is 12.You then have the fraction of 3/12. Then, you multiply 2*4 because again, what you do to the top, you also do to the bottom, so you would also have the fraction of 8/12.The rest is easy. 3/12 + 8/12 is 11/12.And the missing piece of 11/12 is 1/12, because that made it whole.
Hope that helps!