(-7)+( )=21,31+(?)=-85,)-(-21)=37,)-56=-40,
(-7)+( )=21,31+(?)=-85,)-(-21)=37,)-56=-40,
-7+( )=21 31+( )=-85 ( )-56=-40
填空 ·1.(-7)+( )=21 2.31+()=-85 3.()-(-21)=37 4.()-56=-40 计算1.
7/6+13/12+21/20+30/31+42/43+57/56+73/72+91/90=?
21:()=()÷56=7分之8=72分之()=()%
小学二年级数学题56÷()=(3)×7=21÷()=7
怎么简便计算66×21+19×21+85×19=?
111+101+91+.+41+31+21=?
67+21+56-3+1=?
解方程:10.5+x+21=56
( )除以40=( )分之21=( ):( )=7除以8=( )%
8/7=( )/( )=21/( )=40/( )=( )填小数.