1
They are: 12 and 1 because 12*1 = 12 but 12-1 = 11
2 and 11
21
11x5
There are millions of combinations of numbers with a difference of 9. 9 and 0, 10 and 1, 11 and 2, 12 and 3, and so on. The difference is the answer that you get when you subtract two numbers, so any numbers that subtract to an answer of 9 will work.
Among the real whole numbers, you only have two choices: -1 x 11 and 1 x -11
11
1 and 11
11 and 11
-11
2 and 11
26
7 x 11
21
11x5
There are millions of combinations of numbers with a difference of 9. 9 and 0, 10 and 1, 11 and 2, 12 and 3, and so on. The difference is the answer that you get when you subtract two numbers, so any numbers that subtract to an answer of 9 will work.
Among the real whole numbers, you only have two choices: -1 x 11 and 1 x -11
51