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简介:
一、运用加法运算律简算
1.5.26+4.6+4.74
=5.26+4.74+4.6
=10+4.6
=14.6 (加法交换律)
2.2.6+6.92+3.4+0.08
=(2.6+3.4)+(6.92+0.08)
=6+7
=13 (加法分配律)
二、运用减法的性质简算
3.11.34-(7.34+2.25)
=11.34-7.34-2.25
=4-2.25
=1.75
4.2.37-(2.4-1.63)
=2.37-2.4+1.63
=2.37+1.63-2.4
=4-2.4
=1.6
三、运用凑整法简算
5.33.28-19.41+16.62-20.59
=33.28+16.62-19.41-20.59
=33.28+16.62-(19.41+20.59)
=49.9-40
=9.9
6.3.56-1.72+2.44
=3.56+2.44-1.72
=6-1.72
=4.28
四、运用基准数法简算
7.7.0.9+0.99+0.999+0.9999
=(1-0.1)+(1-0.01)+(1-0.001)+(1-0.0001)
=1+1+1+1-(0.1+0.01+0.001+0.0001)
=4-0.1111
=3.8889 (以1为基准)
8.9.6+9.7+9.8+9.9
=(10-0.4)+(10-0.3)+(10-0.2)+(10-0.1)
=10+10+10+10-(0.4+0.3+0.2+0.1)
=40-1
=39 (以10为基准)