问题
计算题
(1)202×198
(2)1022
答案
解:
(1)202×198
=(200+2)(200﹣2)
=2002﹣22
=40000﹣4
=39996;
(2)1022
=(100+2)2
=1002+2×100×2+22
=10000+400+4
=10404.
(1)202×198
(2)1022
解:
(1)202×198
=(200+2)(200﹣2)
=2002﹣22
=40000﹣4
=39996;
(2)1022
=(100+2)2
=1002+2×100×2+22
=10000+400+4
=10404.