the sum of all digits in each pair is 19 and the sum of the numbers in each pair is 100.

Question

I don't understand what the question is trying to ask? Is it to find that number, or?

Answer 1

first thing I want to know, is: which pairs?

Answer 2

Some candidates are

36 64
53 47
...

Answer 3

that's the thing. they don't list any pairs.

Answer 4

well, just pick any 2-digit number, uv
The 2nd number will be (9-u)(10-v)

so, these are also good:

22 78
88 12
...

Answer 5

ok. thanks for the help.