What is the value of 2° +2-1+2-??

Bruce is getting materials for a chemistry experiment his teacher gives him a container that has 0.25 liter of liquid in it.bruce need to use 0.4 of this liquid for the experiment. how much liquid will bruce use?

Solve 2x+y=3 x+y=5 in substitution method

Yesterday i ran 5 miles. today, i ran 3.7 miles. did my percent increase, decrease or is it a percent error? plz i need