99991/5+9991/5+991/5+91/5+41/5怎么简便计算9999又1/5+999又1/5+99又1/5+9又1/5+4又4/5怎么简便计算

问题描述:

99991/5+9991/5+991/5+91/5+41/5怎么简便计算
9999又1/5+999又1/5+99又1/5+9又1/5+4又4/5怎么简便计算

99991/5+9991/5+991/5+91/5+41/5
=(99991+9+9991+9+991+9+91+9+5)/5
=(100000+10000+1000+100+5)/5
=111105/5
=22221

原式=(100000-9)/5 +(10000-9)/5 +(1000-9)/5 + (100-9)/5 + (50-9)/5
=100000/5 + 10000/5 + 1000/5 + 100/5 + 50/5 - 45/5
=20000 + 2000 + 200 + 20+ 10- 9
=22221

99991/5+9991/5+991/5+91/5+41/5
=(100000+10000+1000+100)/5-9*4/5+41/5
=22220+1
=22221

每一项的分子加上9再减去9,凑成10的倍数,再计算
原式=(99991+9-9)/5+。。。(41+9-9)/5
=20000+2000+200+20+10-五个9/5
=22230-9=22221