In the problem 10-4=6 what is the correct term for the number 4

Hannah works at the mall selling book bags. she sold 35 book bags in 5 hours. how many book bags did she sell per hour?

What is the length of the midsegment of a trapezoid with bases of length 15 and 25 ?

Michael gose to a theme park and rides two different roller coasters that both begin on a raised platform his height while on the first roller coaster measured in feet from the platform height can be modeled by the following graph where t is the number of seconds since the ride began