Question

31×870+13×310计算

Answer 1

31×870+13×310计算过程如下
31×870+13×310
＝310×87+13×310
＝310×（87+13）
＝310×100
＝31000

Answer 2

31×870+13×310
=31×870+130×31
=（870+130）×31
=1000×31
=31000