1.흥미로운 합계

1 x 8 + 1 = 9
12 x 8 + 1 = 98
123 x 8 + 1 = 987
1234 x 8 + 1 = 9876
12345 x 8 + 1 = 98765
123456 x 8 + 1 = 987654
1234567 x 8 + 1 = 9876543
12345678 x 8 + 1 = 98765432
123456789 x 8 + 1 = 987654321

9 x 9 + 7 = 88
98 x 9 + 7 = 888
987 x 9 + 7 = 8888
9876 x 9 + 7 = 88888
98765 x 9 + 7 = 888888
987654 x 9 + 7 = 8888888
9876543 x 9 + 7 = 88888888
98765432 x 9 + 7 = 888888888

6539477124183 x 17 x 1 = 1111111111111111
6539477124183 x 17 x 2 = 2222222222222222
6539477124183 x 17 x 3 = 3333333333333333
6539477124183 x 17 x 4 = 4444444444444444
6539477124183 x 17 x 5 = 5555555555555555
6539477124183 x 17 x 6 = 6666666666666666
6539477124183 x 17 x 7 = 7777777777777777
6539477124183 x 17 x 8 = 8888888888888888
6539477124183 x 17 x 9 = 9999999999999999

1 x 9 - 1 = 8
21 x 9 - 1 = 188
321 x 9 - 1 = 2888
4321 x 9 - 1 = 38888
54321 x 9 - 1 = 488888
654321 x 9 - 1 = 5888888
7654321 x 9 - 1 = 68888888
87654321 x 9 - 1 = 788888888
987654321 x 9 - 1 = 8888888888

1 x 9 + 2 = 11
12x 9 + 2 = 111
123x 9 + 2 = 1111
1234x 9 + 2 = 11111
12345x 9 + 2 = 111111
123456x 9 + 2 = 1111111
1234567x 9 + 2 = 11111111
12345678x 9 + 2 = 111111111


2. 2,520이라는 수

-2,520은 1,2,3,4,5,6,7,8,9,10,12,14,15,18,20,21,14로 나누어지는 숫자이다.


3.특이한 숫자 \\\'37\\\'

111 ÷ 37 = 3
222 ÷ 37 = 6
333 ÷ 37 = 9
444 ÷ 37 = 12
555 ÷ 37 = 15
666 ÷ 37 = 18
777 ÷ 37 = 21
888 ÷ 37 = 24