如题所述
第1个回答 2021-04-17
31×870+13×310
=31×870+130×31
=31×(870+130)
=31×1000
=31000
=31×870+130×31
=31×(870+130)
=31×1000
=31000
第2个回答 2021-04-17
31×870+13×310
=310×87+13×310
=310×(87+13)
=310×100
=31000
=310×87+13×310
=310×(87+13)
=310×100
=31000
第3个回答 2021-04-17
31×870+13×310
=31×87×10+13×31×10
=31×10×(87+13)
=310×100
=31000
=31×87×10+13×31×10
=31×10×(87+13)
=310×100
=31000
第4个回答 2021-04-17
31×870+13×310
=310×87+13×310
=310×(87+13)
=310×100
=31000
=310×87+13×310
=310×(87+13)
=310×100
=31000
第5个回答 2021-04-17
31×870+13×31×10
=31×(870+130)
=31×1000
=31000
=31×(870+130)
=31×1000
=31000