Answer :

Palindromic is where if you flip the number around (123 would become 321) then it is the same so:
303
313
323
343
353
363
373
383
393
so there are 10
AL2006

A palindrome is something that reads the same forwards and backwards.

If the number is a palindrome and it's between 300 and 400, then the
last digit must also be a ' 3 '. 

So all we have left to fill in is the digit in the middle.

There are 10 possibilities for that one ... the digits ' 0 ' through ' 9 '.

So there are 10 palindromic numbers between 300 and 400.