2018x2020-2017x2021如何巧算?

2024-10-31 19:30:23
推荐回答(2个)
回答1:

解:原式=(2017+1)*2020-2017*(2020+1)
=2017*2020+2020-2017*2020-2017
=2020-2017=3

回答2:

2018x2020-2017x2021
=2017x2020+2020-2017x2020-2017
=2017x2020-2017x2020+2020-2017
=2020-2017
=3