((2-1 1/3)-(2,75-1,(3))-(1/4-2 3/4))÷2,625
(-9/3-(2,75-3)-(1/4-3/2))÷21/8=(-3-(-0,25)-(-5/4))*8/21=(-3+0,25+5/4)*8/21=(-3+1/4+5/4)*8/21=-3/2*8/21=-4/7