20202021x20212020-20202020x20212021简便计算？

答案：10000

解析：

20202021x20212020-20202020x20212021

=（20202020+1）x20212020-20202020x20212021

=20202020x20212020+1x20212020-20202020x20212021

=20202020x20212020-20202020x20212021+20212020

=20202020x(20212020-20212021)+20212020

=(-20202020)+20212020

=10000

1

原式=10000

设20202020=A 20212020=B
(A+1)xB-A(B+1)
=AB+B-AB-A
=B-A
=20212020-20202020
=10000

设：A=20202020

B=20212020
原式变换为：（A+1）B — A（B+1）
=AB+B — AB — A
=B—A
=20212020— 20202020
=10000