There is 4/5 lb of sand in the class science supplies. if one scoop of sand weighs 1/20 lb, how many scoops of sand can maria get from the class supplies and still leave 1/2 lb in the supplies

With the bag having 4/5 lb currently in it, this can be translated to 16/20 lb. Maria wants to scoop out sand until the bag has 1/2 lb, which is 10/20 lb. The scoop that Maria uses is 1/20 lb, so using the equation of 16-10 = 6, Maria can get 6 scoops of sand before the bag contains 1/2 lb.

Gotta be d the music of previous eras