如题所述
1.(1/69+2/71)ä¹23+25é¤ä»¥71
=1/69*23+2/71*23+25/71
=1/3+(46/71+25/71)
=1/3+1
=4/3
2.(1+1/2)ä¹(1-1/2)ä¹(1+1/3)ä¹(1-1/3)ä¹........ä¹(1+1/9)ä¹(1-1/9)
=3/2*1/2*4/3*2/3...*10/9*8/9
=1/2*10/9(ä¸é´çé½çº¦å»äºï¼
=5/9
3.1/2ä¹3+1/3ä¹4+.......+1/19ä¹20
=1/2-1/3+1/3-1/4+...+1/19-1/20
=1/2-1/20
=9/20
4.1/27+505/2727+131313/272727
=1/27+5*101/(27*101)+13*10101/(27*10101)
=1/27+5/27+13/27
=19/27
5.100-98+96-94+....+4-2
=(100-98)+(96-94)+...(4-2)
=2+2+...+2(å ±æ25个ï¼
=2*25
=50
äºåäºåäºåäºåä¹åä¸Ã79.45+159Ã47.56+ä¸åä¹åäºååä¹åä¸Ã52.44
=52.44Ã79.45+159Ã47.56+79.55Ã52.44
=52.44Ã(79.45+79.55)+159Ã47.56
=52.44Ã159+159Ã47.56
=159Ã(52.44+47.56)
=159Ã100
=15900
=1/69*23+2/71*23+25/71
=1/3+(46/71+25/71)
=1/3+1
=4/3
2.(1+1/2)ä¹(1-1/2)ä¹(1+1/3)ä¹(1-1/3)ä¹........ä¹(1+1/9)ä¹(1-1/9)
=3/2*1/2*4/3*2/3...*10/9*8/9
=1/2*10/9(ä¸é´çé½çº¦å»äºï¼
=5/9
3.1/2ä¹3+1/3ä¹4+.......+1/19ä¹20
=1/2-1/3+1/3-1/4+...+1/19-1/20
=1/2-1/20
=9/20
4.1/27+505/2727+131313/272727
=1/27+5*101/(27*101)+13*10101/(27*10101)
=1/27+5/27+13/27
=19/27
5.100-98+96-94+....+4-2
=(100-98)+(96-94)+...(4-2)
=2+2+...+2(å ±æ25个ï¼
=2*25
=50
äºåäºåäºåäºåä¹åä¸Ã79.45+159Ã47.56+ä¸åä¹åäºååä¹åä¸Ã52.44
=52.44Ã79.45+159Ã47.56+79.55Ã52.44
=52.44Ã(79.45+79.55)+159Ã47.56
=52.44Ã159+159Ã47.56
=159Ã(52.44+47.56)
=159Ã100
=15900
温馨提示：答案为网友推荐，仅供参考
