As given,
Step 1: Pick any three-digit counting number
Lets pick the number 643
Step 2: Reverse the digits of the original number.
So, reverse becomes 346
Now, it says that the difference of these two numbers has a tens digit of 9.
Lets, check:
[tex]643-346=297[/tex]
So, its true that the difference has a tens digit of 9.
Another example:
Lets take 449
So reverse is = 944
Difference = [tex]944-449=495[/tex]
Here also the tens digit is 9.
So, the condition applies to all 3 digit numbers.
