Answer :

A number is divisible by 10 if its last digit is 0. Let's check each number:

1. For [tex]$209$[/tex], the last digit is [tex]$9$[/tex], so
[tex]$$
209 \mod 10 = 9.
$$[/tex]
Since [tex]$9 \neq 0$[/tex], [tex]$209$[/tex] is not divisible by 10.

2. For [tex]$210$[/tex], the last digit is [tex]$0$[/tex], so
[tex]$$
210 \mod 10 = 0.
$$[/tex]
Since [tex]$0 = 0$[/tex], [tex]$210$[/tex] is divisible by 10.

3. For [tex]$181$[/tex], the last digit is [tex]$1$[/tex], so
[tex]$$
181 \mod 10 = 1.
$$[/tex]
Since [tex]$1 \neq 0$[/tex], [tex]$181$[/tex] is not divisible by 10.

Thus, the number that is divisible by 10 is:

[tex]$$
210.
$$[/tex]