Final answer:
To find out how much of the tree house was left to build, subtract the amount already built from the total. Mike built 1/2 on Saturday and another 1/4 on Sunday. The amount left to build is 1/4 of the tree house.
Step-by-step explanation:
To find out how much of the tree house was left to build, we need to subtract the amount already built from the total. Mike built 1/2 of the tree house on Saturday and another 1/4 on Sunday. So, the total amount built is 1/2 + 1/4 = 3/4.
To find the amount left, we subtract the total amount built from 1 (since 1 represents the whole tree house). So, the amount left to build is 1 - 3/4 = 1/4.
Therefore, 1/4 of the tree house is left to build.