求50道递等式运算

30.8÷[14-(9.85+1.07)]
[60-(9.5+28.9)]÷0.18
2.881÷0.43-0.24×3.5
20×[(2.44-1.8)÷0.4+0.15]
28-(3.4+1.25×2.4)
2.55×7.1+2.45×7.1
777×9+1111×3
0.8×[15.5-(3.21+5.79)]
(31.8+3.2×4) ÷ 5
31.5×4÷(6+3)
0.64×25×7.8+2.2
2÷2.5+2.5÷2
36.25÷4.25×9.9
5180－705×6
24÷2.4－2.5×0.8
(4121+2389)÷7
671×15-974
469×12+1492
19.4×6.1×2.3
5.67×0.2-0.62
18.1×0.92+3.93
0.4×0.7×0.25
0.78+5.436+1
4. 8× 5÷4+1÷4
9. 9x5÷6+5÷6
10. 3÷4x8÷9-1÷3
14. 31x5÷6-5÷6
16. 5÷9x18-14x2÷7
20. 3x2÷9+1÷3
35. 95÷（64-45）
36. 178-145÷5×6+42
7.2÷0.8-1.2×5
6.5×（4.8-1.2×4）
28-(3.4+1.25×2.4)
2.55×7.1+2.45×7.1
777×9+1111×3
（31.8+3.2×4）÷5
31.5×4÷(6+3)
0.64×25×7.8+2.2
2÷2.5+2.5÷2
194－64.8÷1.8×0.9
36.72÷4.25×9.9
5180－705×6
24÷2.4－2.5×0.8
(4121+2389)÷7
671×15-974
469×12+1492
405×(