5⋅(64:8+49:7+5⋅1):20=5⋅ : 20 = : 20 = .
5⋅(64:8+49:7+5⋅1):20=5*(8+7+5):20=5*20:20=100:20=5
5*(8+7+5)/20=5*20/20=100/20=5