4/3-7/12+9/20-11/33+13/42-15/56
来源:百度知道 编辑:UC知道 时间:2024/06/03 07:17:29
4/3-7/12+9/20-11/33+13/42-15/56
简便方法计算
简便方法计算
中间一项疑为-11/30??
4/3-7/12+9/20-11/30+13/42-15/56 =
=1+1/3-1/3-1/4+1/4+1/5-1/5-1/6+1/6+1/7-1/7-1/8=
=1-1/8=
=7/8.
你写错了吧,应该是11/30哦,4/3=1/1+1/3,7/12=1/3+1/4,9/20=1/4+1/5,11/30=1/5+1/6,13/42=1/6+1/7,15/56=1/7+1/8。所以原式=1/1+1/3-1/3-1/4+1/4+1/5-1/5-1/6+1/6+1/7-1/7-1/8=1-1/8=7/8
逐个通分吧
(-72)*(3/4-1/6-7/9)
1/(2/3)/(3/4)/(4/5)/(5/6)/(6/7)/(7/8)
3,7/4,1,1/2,( )?
4/3,1,2,7,( )
1 2/3 5/9 (?) 7/15 4/9 4/9
-4/9,10/9,4/3,7/9,1/9,( )。
1/1+(2/1-1/2)+(3/1-2/2+1/3)+(4/1-3/2+2/3-1/4)+...+(9/1-8/2+7/3-6/4+5/5-4/6+3/7-2/8+1/9=
(3*4*5*6*7*8)(1/3+1/4+1/5+1/6+1/7+1/8)
1+1/2+1/3+1/4+1/5+1/6+1/7+1/8+......+1/100 = ?
奥数题:1/2/3/4/5/6/7/8/9=2.8