Let's think a bit like an algorithm. We're given a set of values, 4,5,6 as input and 6,7,8 as output. 

We need to change the function result() to get from the input to the output. For a start, let's try adding 1.

We can see that the output we have is not the output we want, but we got closer to what we want. Let's tweak the code a bit.