2300 tens can be named as 23 thousand or 230 hundreds.
If it says x tens, just multiply x by 10 and you'll get the most proper form of a result. If it says x hundreds, do the same but with a 100, not 10.
89 thousand can be named as 890 hundreds or 8900 tens.
It's generally the same as above, just do division instead of multiplying.