二、计算. ① 0.625×50+0.625×3.46+5.346×3.75 ② 1+1/2+1/6+1/12+1/20+1/30+1/30+1/42+1/56 ③ （7/9
问题描述：
二、计算. ① 0.625×50+0.625×3.46+5.346×3.75 ② 1+1/2+1/6+1/12+1/20+1/30+1/30+1/42+1/56 ③ （7/9
答
0.625*50+0.625*3.46+5.346*3.75
=0.625*(50+3.46)+53.46*0.375
=53.46*(0.625+0.375)
=53.46*1
=53.46
答
① 0.625×50+0.625×3.46+5.346×3.75
=6.25*5+0.625*3.46+（5+0.346）*3.75
=(6.25+3.75)*5+3.46*(0.625+0.375)
=50+3.46
=53.46
② 1+1/2+1/6+1/12+1/20+1/30+1/30+1/42+1/56
=1+1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8
=2-1/8
=15/8
答
偶滴神啊!用计算器啊!不必要在计算上来浪费时间的