Mathematics
Math on the General test is applied arithmetic, not calculus: fractions, ratio and proportion, percentage, area and volume, unit conversion, and the formulas already used in weight and balance and electricity.
Working with numbers. Convert fractions to decimals before multiplying, and carry units so they cancel. In ratio and proportion, cross-multiply. Percentage change is (new − old) ÷ old × 100. Round only at the end and keep the significant figures the problem provides.
Geometry. Area of a rectangle = length × width; triangle = ½ base × height; circle = πr², or 0.7854 d². Volume of a cylinder = area of the base × height. Circumference = πd.
Conversions worth memorizing. 1 gallon = 231 cubic inches; 1 cubic foot = 1,728 cubic inches; 1 inch = 2.54 cm; 1 kg = 2.2046 lb; degrees C = (degrees F − 32) × 5/9.
Applied formulas. Ohm's law and power; CG = total moment ÷ total weight; gear ratio = driven teeth ÷ driving teeth.
Traps. Mixing inches and feet in the same problem, forgetting to halve the diameter before squaring it, and confusing U.S. and imperial gallons.
Worked example. Volume of one cylinder with a 5.125-inch bore and 4.375-inch stroke: area = 0.7854 × 5.125² = 20.63 in²; volume = 20.63 × 4.375 = 90.3 in³. For six cylinders the displacement is about 542 in³.