Mason stands on the 5th step of a vertical ladder. the ladder has 15 steps, and the height difference between consecutive steps is 0.5m. h(n) models the height above the ground of mason's feet (in m) after moving n steps (if mason went down the ladder, n is negative). which number type is more appropriate for the domain of h? what's the appropriate domain?

Which number type?  I'd go with Whole numbers or integers, since the steps are just whole values one step after the next.

well, an appropriate domain, namely the inputs, well, He's on the 5th step, there are 15 steps, so he's really 10 steps away from the top of the ladder, and going down N being negative, he's -5 steps from the ground.

{ N | N ∈ ℤ ,  -5 ⩽ N ⩽ 10 }

If jon had $4.00 then takes away $2.25, then he should have $1.75 left. $4.00 - $2.25 = $1.75 hope this ; )