Everything you need for a quick calculation or two!
Masterwork Tools, mathematical/cartography (masterwork only). 50 GP, 1lb
Equally useful to mathematicians and cartographers, this set of tools provides everything you need for either field. Since no checks are generally involved with either field, these do not provide any bonus beyond the obvious fact that you HAVE the items in question! It is mostly used for role-playing purposes.
Contains a compass (the kind that draws circles, of course), abacus, folding ruler (18" in 3 6" sections), protractor, a thin stick of charcoal held in a hollow wooden tube (read: pencil), and a malleable ruber-like blob for rubbing out the charcoal (read: soft eraser).
Additionally, the mathematica version contains a handy table of common equations and constants (pi, roots out to around 20, a sine table for 0 to 90 degrees in .1 degree steps, and tangent and cosecant tables in 5-degree intervals, and others as appropriate, all out to at least 10 decimals), 50 feet of thin string (think yo-yo string, insufficient to hold weight, used for measuring), knotted at 6" intervals (50 feet long after knots), and a plumb bob.
For Cartographers, a table of known distances, travel times, and key constellations, a set of what we would call french curves, and paperweights are included.
The entire kit is held in a small wooden case, and the compass has three interchangeable points for the non-pointy end: a second point (used to measure), a charcoal attachment (for draft work), and a ink point (for final products).