用简便方法计算800÷25 (125×25)×8 57×15+42×15+15.
64×2.5×0.125 3×0.8+3×2.2 3.76÷0.4÷2.5(14.21+3.5)÷7 4.66×0.28+4.66×0.82﹣4.66 2.4+57.6÷36.
脱式计算.(能简算的要简算)15.58÷8.2﹣0.72 9.6+9.9×99 8×3.6+1.4×2.8 0.74×4×0.25×4.
计算:31.3×7.7+11+8.85+0.368×230=
7.5×2.3+1.9×2.5.
用递等式计算:(能简算的要简算)(1)21.36÷0.8﹣12.9 (2)15.4×103﹣1.54×30(3)29.61÷9.4×1.4 (4)(16.2﹣0.54)÷1.8.