What two simpler problems can you use to find 7 times 38

You could do 7 x 40 and take off (7 x 2)

or 5 x 38 and add (2 x 38).

To do a simpler problem to find the solution, factorize any of the two numbers into multiplied numbers and simplify.
So try to break down 7 into its factors. Well, we can't do that since 7 is prime and has no other factors.
38, however, has factors that we can simplify 38 into.

7 x 38
7 x 2 x 19
7 x 19 x 2

So the two simpler problems are:
7 x 19 x 2 
and 
7 x 2 x 19

Hope this helps :)

The correct answer is -4