iPhone: The Missing Manual, 2nd Edition

Calculator

The iPhone wouldn't be much of a computer without a calculator, now would it? And here it is, your everyday memory calculator—with a secret twist.

In its basic four-function mode, you can tap out equations (like 15.4 x 300=) to see the answer at the top.

Tip

When you tap one of the operators (like ×, +, –, or ÷) it sprouts a white outline to help you remember which operation is in progress. Let's see an ordinary calculator do that!

The Memory function works like a short-term storage area that retains numbers temporarily, making it easier to work on complicated problems.

When you tap m+, whatever number is on the screen gets added to the number already in the memory and the mr/mc button glows with a white ring to let you know you've stored something there. Press m– to subtract the currently displayed number from the number in memory.

And what is the number in memory? Press mr/mc to display it—to use it in a subsequent calculation, for example.

Finally, tap mr/mc twice to clear the memory and do away with the white ring.

Oh—and now the twist: If you rotate the iPhone 90 degrees in either direction, so that it's horizontal, the Calculator magically morphs into a full-blown HP scientific calculator, complete with trigonometry, logarithmic functions, exponents, roots beyond the square root, and so on. Go wild, ye engineers and physicists!