1994+997×997=997×2+997×997=997×999=997×(1000-1)=997000-997=996003
426.37-4.62-26.37-5.35=426.37-26.37-(4.62+5.35)=400-10.07=389.93
6.18×3.22-22.2×0.618=6.18 ×(3.22-22.2×0.1)=6.18×1=6.18
10.25+100.25+1000.25-0.75=(10+100+1000)+(0.25 +0.25+0.25)-0.75=10+100+1000=1110
148.3-{48.3-29.7} =148.3-48.3+29.7=100+29.7=129.7
这样应该够详细了吧?你看可以吗?