618² + 382² + 2 x 618 x 382

(17386 + 73861 + 38617 + 86173 + 61738)/5

12 * 629 * 639563956395 - 629 * 6395 * 1200120012

78 * 82 - 70 * 90

這是我做完後他給我的獎勵：

這是我提交的解答：

618² + 382² + 2 x 618 x 382

= (618 + 382) (618 + 382)
= 1000*1000
= 1000000

(17386 + 73861 + 38617 + 86173 + 61738)/5
= (1 + 7 + 3 + 8 + 6)(10000 + 1000 + 100 + 10 + 1)/5
= 25 * 11111 / 5
= 5 * 11111
= 55555

12 * 629 * 639563956395 - 629 * 6395 * 1200120012
= 12 * 629 * 6395 * (100010001) - 629 * 6395 * 1200120012
= 629 * 6395 * (1200120012) - 629 * 6395 * 1200120012
= 0

78 * 82 - 70 * 90
= (80 - 2)(80 + 2) - 70 * 90
= 80*80 - 2*2 - 70 * 90
= 6400 - 6300 - 4
= 96