Calculations with a calculator of the pin wheel (Odhner) type.

Calculations with a calculator of the pin wheel (Odhner) type



Addition

The first number is entered into the setting-board. By means of a positive turn of the crank this value is trans-
ported to the result-register. In the same way we can add a second number to the value in the result-register.
Example: 85607 + 439 = ?
  1. Zeroise all registers.
  2. Cariage in extreme left position.
  3. Set the first number 85607 with the setting board (positions 5-1)
  4. Enter this number into the result-register by means of a positive turn on the crank.
  5. Zeroise levers (setting-board).
  6. Set the second number 439 (3-1).
  7. Add this number by means of a positive turn on the crank.
  8. Read the result 86046.

Substraction

A number can be substracted by means of a negative turn of the crank at step 7 of the addition. If a substrac-
tion should give a negative number, then the result is the arithmetical complement of this negative number.
For example -2 is indicated as 99999998.

Multiplication

A multiplication can be carried out by repeated addition. For example 3 * 2 = 2 + 2 + 2 = 6. With multiplication
with larger numbers (for example 123 * 234) is not needed to turn arround the crank 123 times. For this multi-
plications we can split the calculation by using the cariage as 3 * 234 + 20 * 234 + 100 * 234 = 234 + 234 + 234 +
2340 + 2340 + 23400. example: 123 * 234
  1. Zeroise all registers.
  2. Cariage in extreme left position, thus the 1th position.
  3. Set the number 234 with the setting board (positions 3-1)
  4. Turn around the crank three times (234 + 234 + 234).
  5. Move the carriage one step to the right, thus to 2th position.
  6. Turn around the crank two times ( + 2340 + 2340).
  7. Move the carriage one step to the right, thus to 3th position.
  8. Turn around the crank one times ( + 23400).
  9. Read the result 28782.

Division ( with arithmetical complement in the Results-register

The dividend is entered into the result-register by means of a negative turn of the crank, so that the mechanical
complement appears. After the divisor is set on the levers, the figures in the result-register are evened out to
zero by means of possitive turns.
Example: 85607 : 439 = ?
  1. Zeroise all registers.
  2. Cariage in extreme right position.
  3. Set the dividend 85607 (positions 6-2)
  4. Enter the dividend into the result-register by means of a negative turn on the crank.
  5. Zeroise levers and proof-register.
  6. Set the divisor 439 (6-4).
  7. Make positive turns - observing the bell, which warns for turns in excess, and moving the cariage step
    by step to the left - until the figures in the result-register are as close to zero possible. Make
    consequently 1 (8), 9 (7), 5 (6), 4 (3), 5 (2), and 5 (1) positive turns.
  8. Read the result 195.00455.

Square roots

The mechanical method of finding square roots is based on the following formula:
1 + 3 + 5 + 7 + 9 + 11 + ... + (2n-3) + (2n-1) = n^2
Example: SQRT(966289) = 983
  1. Zeroise all registers.
  2. Enter 966289 in dials 13-8 of the result-register.
    1. Zeroise the proof-register.
    2. Zeroise the levers.
    3. Divide by the decimal points 966289 in groups of 2 figures each starting from the right, (by decimal
      figures start from the left i.e. from the decimal point).
    4. Carriage in 8th position.
  3. Set the 5th lever at 1, and substract it by means of a negative turn from the left hand group 96. Move
    the same lever to 3, and then to 5, 7, 9, 11 (5th and 6th lever), 13, 15, 17 and 19, and each time you
    make one negative turn. When you make the turn with 19 on the levers the bell will ring. Make therefore
    a positive turn. Reduce the number set on the levers by one unit, thus to 18.
  4. Move the carriage one step, thus to 7th position. Set the fourth lever at 1, and substract successively
    181, 183, 187, 189, 191, 193, 195, 197. At the last substraction the bell will ring. Make therefore a positive
    turn. Reduce the number by one unit, thus to 196.
  5. Move the carriage one step, thus to 6th position. Substract successively 1961, 1963 and 1965. After the last
    substraction the result-register shows 0. The proof-register shows the square root 983.


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