Google is also a math tool

 I know this one's old but not so many know or realize this yet. The Big G is also a good calculator and a math tool useful for a variety of numerical problem solving needs. Google's search capability does not end with just scouring the web for content but it also does basic and not so basic math computations. Google is a good converter capable of handling figures involving almost anything. Key in a number and calibration with another keyword for the converted figure you intend to get and voila, the answer pops up right on top of the search results. Try weight numbers like "178 lbs to kg" and there's definitely an accurate answer to find. You can also try solving light years equivalent in miles or kilometers. Also get square roots and solve long arithmetic problems with Google already remembering MDAS and DPMA rules for you.