【推荐1】列式计算
①一个数的 等于12的 ，它的80%是多少？
②75的40%就是25的几分之几？

【推荐2】直接写出得数．
6-+= 1-0.675= 1÷20%+0.36+0.4=
÷= （+）×12= 1.25×0.9×80=
+-+= 2.6×7.5+74×75%=
×7÷×7= 199+200+201+202+203+204+205=

【推荐3】选择你认为最合理的方法计算.

【推荐1】用你喜欢的方法计算下面各题．
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【推荐2】用递等式计算.
35×+35×             ﹣+-          （+）×60          [1﹣（﹣）]÷

【推荐3】简算．
30%×3/7+3/10×4/7                 2/5×3/8+1/4×1
（1/2+1/3+1/4）×36               20%×30%+1/5×7/10

【推荐1】用简便方法计算下面各题。
27.3+73.2+72.7                                           7.35-(5.2-2.65)
1.7+1.52+8.3+16.48                                76.8-27.4-12.6
5.85+1.89-2.85                                           5.18+6.67+4.82+5.33

【推荐2】脱式计算，能简算的就简算．
1.2×2.5＋0.8×2.5                 0.78×98             1.6×7.5×1.25
2.07÷0.23÷0.45          9.07-22.78÷3.4

【推荐3】脱式计算，怎样简便就怎样算。
21÷0.25÷0.4                                   3.5×0.7+5.5×0.7+0.7
0.36×2.5+0.64×2.5                                     12.75-4.5×0.8
(14.7+8.4)÷0.7                                           0.4×12.5×0.25×8
0.125×3.2×0.25                                          0.648÷(0.4+0.5)×0.6
3.2×1.25×25                                             3.25-0.8×3.25