iris bulbs?

I purchased iris blubs not rhizones 5 of Prof. Blaauw and 5 of Apollow. Can any one tell me if these multiply or do I need to buy more?

Thanks

Your Dutch Iris bulbs will multiply over time, but not as rapidly or in as great numbers as some of the other bulbs, like freesia. They're worth the wait, though. You pretty much get one bloom stem per bulb, but as the bulbs multiply, you'll get more and more with each year.

Thank you, I think the bulbs were 10cents each so I think I will go back and get more.