Вычислите: 1)11÷13×11÷15+11÷13×2÷15; 2)11÷21×5÷14+17÷21×5÷14; 3)22×7÷11-22×6÷11; 4)12÷19×23÷15-12÷19×4÷15; 5)47÷66×1÷2-25÷66×1÷2;

1) ... = 121/195+22/195 = 143/195 = 11/15
2) ... = 55/294+85/294 = 140/294 = 70/147
3) ... = 164/11-142/11 = 22/11 = 2
4) ... = 276/285-48/285 = 228/285 = 0,8
5) ... = 47/132-25/132 = 22/132 = 1/6

1) 11÷13×11÷15+11÷13×2÷15=11/13*11/15+11/13*2/15=121/195+22/195=143/195=11*13/15*13=11/15

2) 11÷21×5÷14+17÷21×5÷14=11/21*5/14+17/21*5/14=5/14(11/21+17/21)=5/14*28/21=5/14*4/3=5*4/14*3=5*2/7*3=10/21

3) 22×7÷11-22×6÷11=22*7/11-22*6/11=22*(7/11-6/11)=22*1/11=22/11=2

4) 12÷19×23÷15-12÷19×4÷15=12/19*(23/15-4/15)=12/19*19/15=12*19/19*15=12/15

5) 47÷66×1÷2-25÷66×1÷2 = 47/66*1/2-25/66*1/2=1/2*(47/66-25/66)=1/2*22/66=1/2*2/6=2/12=1/6