How do I find the value of ##log 1000##?

The answer is 3.

You can do this in 2 different ways.

One is to just plug it in your calculator, and the other is by hand.

By hand, you need to know that ##log## is the same thing as ##log_10##.

Therefore, if you rewrite the problem as such, you get:

##log_10 1000## = ?

From here, it would be a lot easier to solve this problem by converting the logarithm into exponential form (which is simply something with an exponent, like ##5^2##)

To understand how to do this, refer to the image below:

So therefore we can rewrite the problem as:

##10^? = 1000##

And if you know your exponents right, you'll know that ##10^3=1000##

Hence, the answer is 3.

To know more about how logarithms work, please refer to my explanation in this I contributed to.

Hope that helps :)