999 *1999简便运算

来源：百度知道 编辑：UC知道 时间：2024/06/07 05:54:30
999 乘1999简便运算
还有 824-396 763+298 9999*7778+3333*6666 1234567891的平方-1234567890*1234567892

999 * 1999
= (1000 - 1)(2000 - 1)
= 2000000 - 3000 + 1
= 1997000 + 1
= 1997001

824 - 396
= 824 - (400 - 4)
= 424 + 4
= 428

763 + 298
= 763 + 300 - 2
= 1063 - 2
= 1061

9999 * 7778 + 3333 * 6666
= 3333(3 * 7778 + 6666)
= 9999(7778 + 2222)
= 9999 * 10000
= 99990000

1234567891^2 - 1234567890 * 1234567892
= 1234567891^2 - (1234567891 - 1)(1234567891 + 1)
= 1234567891^2 - (1234567891^2 - 1^2)
= 1

是不是999²+1999？

999*1999
=(1000-1)*(2000 -1)
=1000*2000
=3000000

cout<<999*1999<<" "<<824-396<<" "<<763+298<<" "<<9999*7778+3333*6666<<" "<<1234567891*1234567891<<" "<<1234567890*1234567892<<endl;

ps: 你的问题放错地方了