222 because 222+222=444 and 444/2=222
I am not sure if any two consecutive numbers can add up to an even number.
There are no two prime numbers in which a product of 100 is possible.
19 and 1
A one and two zeros
These two sets together make up the set of real numbers.
342 234 423
1-5
2 and 1021
97 + 2
83 + 2
Hard question
4 and 9.