Examples of typical weight and balance problems (solved  with an electronic calculator) that pilots and airframe and  powerplant (A&P) maintenance technicians encounter  throughout their aviation endeavors are shown later in this  chapter. To determine the CG, use this formula: Determining the CG of an airplane in inches for the main- wheel weighing points can be done with any simple electronic  calculator that has addition (+), subtraction (–), multiplication  (×), and division (÷) functions.  [Figure 10-1] Scientifi calculators with such additional functions as memory (M),  parentheses (( )), plus or minus (+/–), exponential (y$^{x}$),  reciprocal (1/x), and percentage (%) functions allow more  complex problems to be solved or simple problems to be  solved using fewer steps. Key the data into the calculator and press the equal (=) key. The answer should read as follows: The arm of the nosewheel is negative, so the CG is –13.2 or  13.2 inches ahead of the main wheel weighing points. The E6-B uses a special kind of slide rule. Instead of its scales  going from 1 to 10, as on a normal slide rule, both scales  go from 10 to 100. The E6-B cannot be used for addition or  subtraction, but it is useful for making calculations involving  multiplication and division. Its accuracy is limited, but it is  sufficiently accurate for most weight and balance problems. The same problem that was just solved with the electronic  calculator can be solved on an E6-B by following these steps: First, multiply 340 by 78 (disregard the minus sign)  [Figure 10-3] :  According to  Figure 10-2 , the weight of the nosewheel (F) is  340 pounds, the distance between main wheels and nosewheel  (L) is –78 inches, and the total weight (W) of the airplane is  2,006 pounds. L is negative because the nosewheel is ahead  of the main wheels. 10-2 •  Step 2—opposite 78 on the inner scale, read 26.5 on  the outer scale. Determine the value of these digits by estimating: 300 × 80 = 24,000, so 340 × 78 = 26,500. Then, divide 26,500 by 2,006  [Figure 10-4] :  •  Step 1—place 10 on the inner scale (this is the index  opposite 34 on the outer scale that represents 340). Figure 10-1.  A typical electronic calculator is useful for solving  most types of weight and balance problems. CG = F × L  W = 340 × –78 2,006 (340)(×)(78)(+/–)(÷)(2006)(=) –13.2 CG = F × L W = 340 × –78 2,006 Figure 10-2.  Weight and balance data of a typical nosewheel  airplane. Electronic Calculator Weighing Point Weight (lb) Arm (in) 0 0 –78 830 836 340 2,006 Right side Left side Nose Total E6-B Flight Computer