Marcha,

Talking about "rounding to the nearest ten" is misleading, because (say) 20 and 30 are exactly the same distance from 25; there isn't a "nearest" ten. There are various conventions on how to "round fives". Schools usually teach that numbers ending in 5 should be rounded upward. (*)

Whatever: this won't change the hundreds digit.

So the number is where there is a missing digit in the red box

Now what do you get after rounding?

So what's in the red box?

Good Hunting!
-RD

* There is another convention called "round-to-even" or "banker's rounding"; you can look it up if you're curious.