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Copyright 1912

BY THE NORMAN W. HENLEY PUBLISHING CO.

Copyright 1905

By THE DERry-Collard COMPANY

PRESS OF
BRAUNWORTH & CO.

PRINTERS AND BOOKBINDERS

BROOKLYN, N. Y.

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PREFACE.

It was thought that a book of convenient size, containing examples of simple mathematical calculations which come up every day in the work of practical men (a portion of which was originally published in Machinery), together with methods of solving the problems, and explanations in clear language of the principles on which the methods of solution are founded, would be appreciated by those whom it is intended to serve.

The demand for this little book has continued to such an extent that we have revised and enlarged it so as to bring it up to modern pratice in every particular.

The Authors.

MACHINE-SHOP

ARITHMETIC.

Chapter I.

Decimals.

There are few men who do not understand vulgar or common fractions, as it is plain that 1⁄2 means one-half, % means three-eighths, etc., and in plain language we say that the figure below the line (or denominator) shows the number of parts into which the number (or whatever is being considered) is divided, and the figure above the line (numerator) shows how many of these parts are being spoken of.

Decimals or decimal fractions are a

system in which ten is the base (derived from decem meaning ten), and is not a fundamental principle.

In this everything is reduced to tenths, hundredths, thousandths, etc., and the value is determined by the position of the decimal point.

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