用简便方法计算(巧算)
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用简便方法计算(巧算)用简便方法计算(巧算) 用简便方法计算(巧算)(5.8X0.4+7.5X0.4)X2.5=(5.8+7.5)X0.4X2.5=(12+1.3)X4X0.25=13.3X
用简便方法计算(巧算)
用简便方法计算(巧算)
用简便方法计算(巧算)
( 5.8 X 0.4 + 7.5 X 0.4 ) X 2.5
= ( 5.8 + 7.5 ) X 0.4 X 2.5
= ( 12 + 1.3 ) X 4 X 0.25
= 13.3 X 1
= 13.3
1.6 X ( 1.25 + 0.5 )
= 16 X 0.125 + 1.6 X 0.5
= 2 X 1 + 0.8
= 2 + 0.8
= 2.8
2.7 X 4.3 + 27 X 0.48 + 0.27 X 8
= 0.27 X 43 + 0.27 X 48 + 0.27 X 8
= 0.27 X ( 43 + 48 + 1 + 7 )
= 0.27 X 99
= 0.27 X ( 100 - 1 )
= 27 - 0.27
= 26.73