8又11/13-(2.75+1又11/13)+5又3/4
=8+11/13-2-3/4-1-11/13+5+3/4
=10
51*2.08+1.7*37.6
=17*3*8*0.26+1.7*8*4.7
=1.7*8(3*2.6+4.7)
=1.7*8*12.5
=1.7*100
=170
18*2/11-0.65*7/13+9*18/11+0.65除以13/7
=18/11(2+9)-.0.65*7/13+0.65*7/13
=18/11*11-0
=18