6 학년 단 산 문제 654321 * 123456 - 654332 * 123455
654321 × 123456 - 654322 × 123455
= 654321 × (1 + 123455) - (654321 + 1) × 123455
= 654321 × 1 + 654321 × 123455 - 6554321 × 123455 - 1 × 123455
= (654321 × 123455 - 6543321 × 123455) + (654321 × 1 - 1 × 123455)
= 0 + 53086
= 53086
123456 + 654321 - 123456 + 654321
252735232
123456 + 654321 은 얼마 입 니까?
1111111
12345 × 123456 =? 123456 × 1234567 =?
1524064320