.(5.5+6.8×0.65)÷2.5
2.8.12× 6.8÷0.12×12.8
3.（3.2×1.5+2.5）÷1.6
4.5.38+7.85-5.37
5.17.2÷0.8-1.2 6.0.68×1.9+0.32×1.9
7.10.15-10.75×0.4-5.7
8.12.8×（3.27-0.53）+4.2×13.7
9.6.1+9.728÷3.2×2.5
10.（7.1-5.6）×0.9+1.15
11.5.6×（3.7-2.9）+0.83
12.5.5+(12.8-6.8×0.55)÷8.5
13.0.12× 4.8÷0.12