复习旧知-(+5)=+(+5)=-(-7)=+(-7)=-5+5+7-71.化简=(-1)x3+(-1)x(-7)=-3+7=1x3+1x(-7)=3-72.去括号①-(3-7)②+(3-7)+3与-7的和=(-1)x(3-7)=(+1)x(3-7)想一想根据分配律,你能为下面的式子去括号吗?③+(a-b+c)④-...
时间:2024-11-14 06:20栏目:幼儿/小学教育