78×21 19×21 97×19简便计算?

2024-11-23 09:43:10
推荐回答(3个)
回答1:

78×21+19×21+97×19
=21×(78+19)+97×19
=21×97+97×19
=97×(21+19)
=97×40
=3880
加油你可以的

回答2:

78×21 +19×21 +97×19
= (78+19)×21 +97×19
= 97×21 +97×19
= 97×(21+19)

= 97×40
= 3880

回答3:

你这题连加减的符号都没写,要大家来猜?