用简便方法计算的题 3.42×5.7+43×0.342用简便方法怎么做

3.42×5.7+43×0.342用简便方法怎么做  

3.42×5.7+43×0.342用简便方法怎么做

简便方法为3.42*5.7+43*0.342=0.342*57+0.342*43=0.342*（57+43）=0.342*100=34.2

80.6*5.7+43*8.06用简便方法怎么算

80.6*5.7+43*8.06
=80.6*5.7+4.3*80.6
=80.6*(5.7+4.3)
=80.6*10
=806

3.45×5.7 43×0.342的简便记算怎么算

3.45x5.7+43x0.342
=(3.42+0.03)x5.7+4.3x3.42
=3.42x5.7+0.03x5.7+4.3x3.42
=3.42x(5.7+4.3)+0.171
=3.42x10+0.171
=34.2+0.171
=34.371

(-4.2-5.7)+(10+5.7)简便方法怎么做

去括号，得到-4.2-5.7+10+5.7
=10-4.2
=5.8

258-143-43用简便方法怎么做

258-143-43用简便方法怎么做
解：
直接运算最简便，
原式=258-143-43
=115-43
=72

43*78-2用简便方法怎么做

43*78-2用简便方法怎么做
解=（40+3）*（80-2）-2
=3200-80+240-6-2
=3200+152
=3352

43×203减3×43简便方法怎么做

43×203-3×43
=43X(203-3)
=43X200
=8600

832减357减43用简便方法怎么做

832-357-43
=832-（357+43）
=832-400
=432