解:1.29*0.38-0.38*0.29等于( 19/50 ),【即等于0.38】
∵已知需求出1.29*0.38-0.38*0.29等于多少
A × B - A × C = A × (B - C)
∴1.29 * 0.38 - 0.38 * 0.29
= 0.38 × (1.29 - 0.29)
= 38/100 × 1
= 38/100
= 19/50
= 0.38
答:1.29*0.38-0.38*0.29等于19/50 ,【即等于0.38】
1.29×0.38-0.38×0.29
=(1.29-0.29)×0.38
=1×0.38
=0.38
运用乘法分配律