In solving problems the process should be not merely indicated, but all the figures necessary in solving each problem should be given in full. The answers to each problem should be indicated by writing “Ans.” after it.
Arithmetic is the science of numbers.
A Number is the result of the comparison (also called measurement) of a magnitude or quantity with another magnitude or quantity of the same kind supposed to be known.
A Concrete Number is one the nature of the unit of which is known.
Denominate Number.—A concrete number the standard of which is fixed by law or established by long usage.
An Abstract Number is one of which the nature of the unit is unknown.
How to Read Numbers.—The right way to read 101,274, etc., is one hundred one, two hundred seventy-four, etc.
The Decimal Point.—A period, called decimal point, is placed in a mixed number between the integral part and the decimal portion which follows. It should never be omitted.
Roman Numbers.—I stands for 1, V for 5, X for 10, L for 50, C for 100, D for 500 and M for 1,000.
Abbreviations.—A smaller unit, written to the left of a greater one, is subtracted from the latter, as: IV = 4 (IV is marked IIII on clock and watch dials); IX = 9; XC = 90; CD = 400, etc. Sometimes a Roman number is surmounted by a dash or vinculum; it then expresses thousands, as IX = 9,000.