Finding and Counting the same value?

I have a question and I hope this is the right area to post this question. I’m a fairly good (general everyday use) excel user but..

I have an excel document that has information in 1000’s rows spread over a few dozen columns. What I’d like to do is figure out the quickest and easiest way to add a formula that will could the total values and put that number where I want it.

Example A1 to A2500 has codes in each row.. 100, 358, 262, 835, 595, 101.. etc right up to 999. The codes are not in order but correspond to other information in the spread sheet. I could sort them and count myself but that takes a long, long time! How can I get excel to search these rows in that column and tell me how many codes between 100 – 150 there are or how many between 100 – 200 there are. I can get it to count up how many 100 or 101 or 102.. etc but not a range of codes over a range of rows.

I hope this makes sense, it’s a fairly complicated spreadsheet but I think if I can get excel to do the hard work for me it’ll make life easier!