二年级上加减加乘混合运算口算

31+5×8=36+3×2=67+2×7=50+2×2=12+7×8=8×2+21=3×4+36=3×6+68=4×6+68=7×5+23=7×3-11=7×7-11=7×3-19=9×7-36=7×