ferent numbers. In the previous example, 12 was

multiplied by 12. Suppose it was necessary to multiply

12 by 31, and 12 by 15. After completing the first

multiplication, the machine reads as follows: upper dials,

12; keyboard, 12; lower dials, 144. To multiply 12 by 31

and by 15.

is not required. Leave the 12 on the keyboard.

rings. Turn the crank forward one turn. (The red 1 in the

in this example. Change the I in the upper dials to 3 with

upper dials is the first digit of the answer). Shift the

two forward turns of the operating crank. Shift carriage

carriage one place to the left. Turn the crank backward

one place to the right. Change 2 in the upper dials to 1

until the bell rings. Turn the crank forward one turn (bell

with one backward turn of operating crank.

also rings on the one forward turn to warn you not to go

any farther).

Upper dials

31

Lower dials

372

one place to the left, turning the crank back until the bell

Answer

rings and turning the crank forward one turn.

In a similar manner, change the upper dials to 15 and the

result should be:

Lower dials

0 (remainder)

Upper dials

15

Upper dials

144 (answer)

Keyboard 12 Lower dials 180

Answer

a turn or two past the bell, simply turn the crank forward

until the bell rings, and stop. Listening for these bells

can be done in either direction. As long as the figures on

makes it possible to perform the division without

the keyboard and in the upper dials are correct, the result

watching the machine.

in the lower dials will be correct.

fractions are expressed as decimals. For example, 1/4 =

process of repeated additions, accomplished by forward

.25, 5/8 = .625, etc. The arrangement of the dials and

turns of the operating crank, so division is a process of

the keyboard makes it particularly adaptable to handling

continued subtractions, accomplished by backward turns

calculations involving decimal numbers. All decimals

of the operating crank. The repeat key must be

can be set for a complete group of problems before

depressed when doing division. For example, to divide

starting the work, and all the calculations can be

1728 by 12:

completed without any resetting of the decimals. The

work is done entirely around preset, fixed decimals. The

one simple rule for setting decimals is as follows:

Keyboard decimal + upper dial decimal = lower dial

decimal.

1728, on the extreme right of the keyboard.

Make one forward turn of the operating crank. Depress

decimal is marked by turning one of the small knurled

the keyboard clear key and turn clear-out crank

wheels below the keyboard to the right so that the yellow

clockwise. (This clears the keyboard and clears the 1

decimal marker appears between the proper keyboard

out of the upper dials).

columns.

move the carriage two spaces to the right so that the

decimals are marked by the gray pointers which can be

divisor, 12, is in direct alinement with 17, the first two

easily positioned to point off the decimal exactly as with

figures of the dividend in the lower dials.

paper and pencil. To set a decimal at two in the dials,

simply set the marker to the left of the two on the slide

.

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