# Google calculator – handy, but not always correct

By Murray Bourne, 27 Aug 2008

Have you ever played with Google’s nifty calculator?

Just go to Google and type something like the following into the search field:

4 + 5

The answer will come back at the top of the search results.

What else can it do? Well, lots, actually.

Try these:

**Raise to a power**– Example: 5^2**Square root**– Example: sqrt(34.7)**Trigonometric functions**– Example: sin(3pi/4) [It assumes the angle is in radians]**Counting**(in the study of probability) – Example: If you need to know the number of ways 5 objects can be chosen from 14 objects, put: 14 choose 5

There are more examples and information here: Google’s calculator.

BTW, you may not need to actually go to Google’s site. If you have Google selected as the search in Firefox, the answer will appear as a “suggestion” and you don’t even need to leave your current page:

## Large Numbers and Calculators

Most hand-held calculators are limited when it comes to large numbers. This is a problem if you want to find the factorial of some large-ish number. For example, an old 8-digit calculator I have here can go up to 69! only (the answer is 1.71122 × 10^{98}). [This answer is almost equal to the number "googol" (10^{100}), which was the number that inspired Google's name.]

Now, on Google’s calculator, I can do up to 170! (The answer is 7.25741562 × 10^{306}). After that, it falls over. But hey, not bad.

## Google’s Calculator Mistakes

Now, what about those mistakes I was talking about? The following article from CNET.com writer Steven Shankland shows that when the numbers are huge, Google’s calculator could be off a bit.

See Google’s math == FAIL! (no longer available)

I tend to agree with the Shankland. Google should put effort into getting this right.

See the 1 Comment below.

27 Aug 2008 at 11:50 pm [Comment permalink]

I tried Google calculator one day yesterday.

It is possible that the large numbers involved in Google’s Math == FAIL was due to overflow errors. The calculator might only be able to read a certain number of significant figures.