Use a unit rate! You can use the rate assignments/hour, meaning how many assignments will you do every hour. This can be written as 8/5 (assignments/hours), or 8/6 (depending on how many hours you give yourself. If you wanted to simplify. you could divide the fractions.
8/5 would become 1.6 (1.6 assignments per hour)
8/6 would become 4/3 (4/3 assignments per hour)
:)