1/3+7/13=() 5/7-2/7=()
()-1/12=11/12 7/5-()=3/5
[主观题]填空。2/7=()/219/12=3/()5÷3=()/()=1又()/()
[单选题]1,1,3,3,7,5,13,7,21,( )。A.9B.11C.8D.22
[单选题]1/3,4/7 ,7/11 ,2/3 ,13/19 ,( )A. 16/21B. 16/23C. 18/21D. 17/21
[主观题]2/3,1/2,3/7,7/18,()A、4/11;B、5/12;C、7/15;D、3/16
[试题]填空:(1)(-7)+()=21;(2)31+()=-85;(3)()-(-21)=37;(4)()-56=-40.
[单选题]1,3,3,6,7,9,13,12,( ),( )。A.19.18B.19,15C.21,15D.27,18
[单选题]1 1 5 7 13 ( )A . 15B . 17C . 19D . 21
[单选题]-27,-7,1,3,5,13,( )A.33B.31C.27D.25
[单选题]:1, 3, 3, 5, 7, 9, 13, 15, ( ), ( )。A.19,21B.19,23C.2l,23D.27,30
[单选题]2,5,1,12,3,2,2,14,2,1,7,36,4,( ),3A.1B.2C.3D.4