John, Tim, & Mike are painting a fence. John paints 1/4 and Tim paints 2/5 of the fence. How much of the fence is left for mike to paint?
The fractions of the fence painted so far are 1/4 and 2/5.
Adding the fractions together gives us: 1/4 + 2/5 = 5/20 + 8/20 = 13/20.
i.e. so far, 13/20 of the fence have been painted.
Therfore the fraction of the fence still left to be painted = 1 - 13/20 = 7/20
Answer: The fraction left for Mike to paint is 7/20