PHP - How to use check with function?

Following are my PHP variables with values,

$value = 234333;

$value = 344665;

$value = 456325;

How to check if number start with 2 or 3 or 4.

If value start with 2 print "this is 2"

If value start with 3 print "this is 3"

If value start with 4 print "this is 4"