I've seen people compute complex arithmetic off the top of their head. How do they do it? [more inside]
posted by Christ, what an asshole on Apr 30, 2009 - 13 answers

Math problem with shipping rates. Can a maths whiz point me in the right direction? [more inside]
posted by dydecker on Apr 14, 2009 - 11 answers

Does anyone know of a php script that can be used to easily generate a web form, and that can have a "calculation" box at the bottom, that will calculate a cost based on the previous response fields? [more inside]
posted by thewibbler on Apr 1, 2009 - 6 answers

I have an Excel question that I'm not sure how to search the archives for. [more inside]
posted by pdb on Nov 4, 2008 - 4 answers

What equation can I use to calculate the number of miles in a degree of longitude for a given latitude? [more inside]
posted by Glendale on Aug 19, 2008 - 9 answers

Math filter: How many equally sized rectangles will fit into a circle, and how should I arrange them in order to make the best-looking approximation? [more inside]
posted by brandnew on Aug 17, 2008 - 9 answers

I drive a 1992 Toyota Camry with just over 203,000 miles on it. As far as I know, the car is in good mechanical condition except that the rear struts are in fairly desperate need of replacement. How do you calculate the payback period for repairing an old but paid-off car, and how might you use this information to help decide whether to repair the car or buy a newer used car? [more inside]
posted by Juffo-Wup on Jul 18, 2008 - 20 answers

I've got an interesting question about MS Acess. It involves using lat/long data... Anyone care to help? [more inside]
posted by dance on Nov 2, 2006 - 15 answers

How do I calculate Gross Profit Percentage (GPP) on goods I sell? [more inside]
posted by tomble on Sep 9, 2006 - 2 answers

I run a computer service. I have an issue that is a bit outside the bounds. I have a client who has been using an Excel spreadsheet to track his portfolio. It is pre-formatted for him to enter data and the formulas are all there. Just recently, it started calculating some things incorrectly. The person who originally set it up just passed away earlier this year. We need an Excel expert that can look at the file and don't know where to begin to find one. Checked the local community college but no dice. All ideas or pointers are appreciated.
posted by titans13 on Aug 17, 2006 - 11 answers

Power Tool Filter: Is there some kind of 'force multiplier' in effect when using a drill press? i.e. when you put two pounds of pressure on the handle, is there more pressure applied to the work surface? Perhaps most importantly, how hard would this be to calculate? [more inside]
posted by schwap23 on Jul 18, 2006 - 6 answers

How can the energy cost of an electronic device over a span of time be calculated?
posted by airguitar on Feb 21, 2006 - 6 answers

How can I calculate the ambient (natural) light level for a particular location and time? [more inside]
posted by orthogonality on Nov 22, 2005 - 9 answers

Myth or truth?: You burn as many calories playing a major theatrical role (i.e. "Hamlet") as you do running a marathon. And how DO you calculate calories, anyway? [more inside]
posted by grumblebee on Jul 8, 2005 - 20 answers

How does my pocket calculator do this? [more inside]
posted by Termite on Mar 28, 2004 - 6 answers