两道小学数学递等式!速度!7.5×2.3+1.9×2.5+22.5×0.4(1+0.12+0.23)×(0.12+0.23+0.34)—(1+0.12+0.23+0.34)×(0.12+0.23)小学5年级没学过.我要巧算,谢谢

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/09 19:45:19

两道小学数学递等式!速度!7.5×2.3+1.9×2.5+22.5×0.4(1+0.12+0.23)×(0.12+0.23+0.34)—(1+0.12+0.23+0.34)×(0.12+0.23)小学5年级没学过.我要巧算,谢谢
两道小学数学递等式!速度!
7.5×2.3+1.9×2.5+22.5×0.4
(1+0.12+0.23)×(0.12+0.23+0.34)—(1+0.12+0.23+0.34)×(0.12+0.23)
小学5年级没学过.
我要巧算,谢谢

两道小学数学递等式!速度!7.5×2.3+1.9×2.5+22.5×0.4(1+0.12+0.23)×(0.12+0.23+0.34)—(1+0.12+0.23+0.34)×(0.12+0.23)小学5年级没学过.我要巧算,谢谢
7.5*2.3+1.9*2.5+22.5*0.4
=2.5*3*2.3+1.9+2.5+2.5*9*0.4
=2.5*(6.9+1.9+3.6)
=2.5*12.4
=2.5*4*3.1
=31
(1+0.12+0.23)*(0.12+0.23+0.34)-(1+0.12+0.23+0.34)*(0.12+0.23)
=(1+0.12+0.23)*(0.12+0.23)+(1+0.12+0.23)*0.34-(1+0.12+0.23)*(0.12+0.23)-0.34*(0.12+0.23)
=0+0.34*(1+0.12+0.23-0.12-0.23)
=0.34