If you work 40 hours per week, how many hours will you work in a year?

What is the missing step in this proof ?

Nick has box brads. he uses 4 brads for the first project. nick let’s b represent the original number of brads and finds that for the second project, the number of brads he uses is 8 more than half the difference of b and 4. write an expression to represent the number of brads he uses for the second project.

Which of the following contains a variable?