根据乘法分配率6×7=6×3+6×46×9=6×4+6×5或6×7+6×2或6×1+6×8或6×3+6×66×6+6=6×7
6x7=6x3+6x46x9=6x3+6x66x6+6=6x7
3 5 4 7
