7.23*9.9-0.723
=7.23*0.99*10-0.723
=7.23*(0.99*10-0.1)
=7.23*9.8
=7.23*(10-0.2)
=7.23*10-7.23*0.2
=72.3-1.446
=70.854
在本题中,看到9.9,就要敏感的想到凑出一个10,那么这道题就可以采用简便运算,然后一步步算出答案即可。
7.23x9.9-0.723
=7.23x9.9-7.23x0.1
=7.23x(9.9-0.1)
=7.23x9.8
=70.854
7.23×9.9+0.723
=7.23×9.9+7.23×0.1
=7.23×(9.9+0.1)
=7.23×10
=72.3
望采纳,啾咪~
7.23×9.9+0.723
=7.23×9.9+7.23×0.1
=7.23×(9.9+0.1)
=7.23×10
=72.3