Operators — compound assignment: +=, -=, *=, /=

Compound assignment operators

x += 5 is shorthand for x = x + 5. Applies to -=, *=, /=, %=, **=.

Challenge: Write compoundAssignment(x) that:

1. Does x += 10
2. Then x -= 3
3. Then x *= 2
4. Then x /= 2
5. Returns x