## Google calculator – handy, but not always correct

[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.

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

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.