Solution: Page 243 (Building of Fun)

Question

What do you press to go four floors up? What do you press to go three floors down?

Solution

1. To go four floors up:

   • Each press of + moves you up one floor.
   • We need to press + four times.
   • Expression: $+4$ or $++++$.

2. To go three floors down:

   • Each press of - moves you down one floor.
   • We need to press - three times.
   • Expression: $-3$ or $---$.