1.括号里填不同的数9/10=1/()+1/()+1/()+1/（）31/221=1/()+1/()+1/()1/6=1/（）+1/()1/6=1/（）+1/()+1/()+1/()1/2=1/()+1/()+1/()1=1/()+1/()+1/()+1/()13/23=1/()+1/()+1/()7/12=1/()+1/()2.下面可以填几?5/7×1又

Question

1.括号里填不同的数
9/10=1/( )+1/( )+1/( )+1/（ ）
31/221=1/( )+1/( )+1/( )
1/6=1/（ ）+1/( )
1/6=1/（ ）+1/( )+1/( )+1/( )
1/2=1/( )+1/( )+1/( )
1=1/( )+1/( )+1/( )+1/( )
13/23=1/( )+1/( )+1/( )
7/12=1/( )+1/( )
2.下面可以填几?
5/7×1又（）/5>1
12×3/8＞4又1/（）
3.在括号里填上相同的数,使等式成立
9+（）/19+( )=2/3
73－( )/136－（ ）=2/9

Answer 1

1,
9/10=18/20=1/20+2/20+5/20+10/20=1/20+1/10+1/4+1/2
31/221=(1+13+17)/221=(3+39+51)/663=1/221+1/17+1/13
1/6=3/18=1/18+2/18=1/18+1/9
1/6=15/90=1/90+2/90+3/90+9/90=1/90+1/45+1/30+1/10
1/2=6/12=1/12+2/12+3/12=1/12+1/6+1/4
1=24/24=2/24+4/24+6/24+12/24=1/12+1/6+1/4+1/2
13/23=52/92=2/92+4/92+46/92=1/46+1/23+1/2
7/12=3/12+4/12=1/4+1/3
2,
5/7(5/5+x/5)=1/7(5+x)=5/7+x/7
x=3,填3
12（3/8）=9/2=4+1/2
4+1/x
x=3 ,填3
3,9+x/19+x=2/3
171+x+19x=38/3
171+20x=38/3
513+60x=38
60x=-475
x=-475/60 填-475/60
73-x/136-x=2/9
9928-x-136x=272/9
9928-137x=272/9
89352-1233x=272
x=89080/1233