Trade math lessons
The drills on this site mark your answers; these pages teach the method first. Each lesson is the same shape — why the arithmetic is the way it is, three examples worked all the way through, the matching drill embedded so you can try it on the spot, and a button that prints twenty fresh questions with an answer key for a class or a lunch break. None of it is a lookup: it is all arithmetic you can reason out, which is exactly why it is worth being quick at.
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Fractions on a tape
Why a tape is in sixteenths, how to reduce, and how to add two marks without a calculator.
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Reading a tape the fast way
Tick lengths, the nearest-long-mark trick, and the habit that stops you miscounting sixteenths.
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Right triangles on the job
3-4-5 for squaring a layout, Pythagoras for the travel of an offset, and where the multipliers come from.
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Metric ↔ imperial without a calculator
25.4 to the inch, 0.3048 to the foot, the rough versions you can do in your head, and when rough is not good enough.
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Percent in the trade
Percent of a number, what percent one number is of another, and increasing by a percent — on numbers you bring.
The electrical side of the arithmetic — Ohm's law at three levels, and series and parallel — lives with its drills at Ohm's law practice and series / parallel practice, each with its own worked examples.
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Leave your email and tick the box for a short heads-up, at most every two weeks, about tools, drills and diagrams that fit what you've been working through — here and on bentright.com and fieldcalc.net. One list across the three, one click to leave, and nothing is sent until you confirm from your inbox.