Simple Bourne shell question

[Jeffrey W Percival]

In the 2.8BSD Bourne shell, are there numeric variables?  For example,
in a for-do-done loop can I initialize a counter and then increment it
in the loop?  Can other arithmetic be done on such variables?  Can their
values be used in echo statements as are strings ( ${string} )?  Please,
2.8BSD replies only, and thanks!

-- 
	Jeff Percival ...!uwvax!uwmacc!jwp