Numbers & Notes for Mac

From The Digital Inkwell:

Numbers & Notes is basically intended to help you do whatever you would do with a calculator, pen, and paper--just a little bit better. Let's start with the "Notes" part: you can put text along with numbers onto the tape to help you more easily keep track of what you're calculating. While you could do this easily enough by hand on a calculator with a physical tape, we haven't found any computer based calculator that allows this. This can be especially useful on saved tapes (and yes, you can save them, too).
Once you have a fairly long tape, if you need to check it against your paper records, you can have Numbers & Notes read back your tape to you. No need to look back and forth from screen to page--although you might want to spend some time choosing a voice you like from the System Preferences. And if you don't want to hear your whole tape, just highlight a selection before you tell Numbers & Notes to speak.
Finally, although we think we know just how the tape should look, why should we decide? Set different colors for the numbers and notes. Make them smaller or larger. Make the tape yellow and negative totals orange. Well, maybe not, but anything short of stripes is up to you. Those are some of the ways you can change the appearance of the tape, but you can also change its behavior: tell it how you want the operators to be spaced. Set whether or not you want a running total.
So even if you just need a calculator to figure out how much you'd get after taxes if you won the lottery, try out Number & Notes. It's cheap, it's big--you don't have to squint at it--and it just looks better, because you make it look the way you want it to.