SIGNS.
COMMERCIAL SIGNS.
| ⅌ | Per, each. |
| @ | At or to. |
| % | Percentum. |
| ℀ | Account. |
| ¢ | Cent. |
| $ | Dollar or dollars. |
| £ | Libra, libræ, pound or pounds sterling. |
| / | Solidus, solidi, shilling or shillings. |
MATHEMATICAL, ALGEBRAICAL, AND GEOMETRICAL.
+ plus, or more, is the sign of real existence of the quantity it stands before, and is called an affirmative or positive sign. It is also the mark of addition: thus, a+b, or 6+9, implies that a is to be added to b, or 6 added to 9.
− minus, or less, before a single quantity, is the sign of negation, or negative existence, showing the quantity to which it is prefixed to be less than nothing. But between quantities it is the sign of subtraction: thus, a−b, or 8−4, implies b subtracted from a, or 8 after 4 has been subtracted.
= equal. The sign of equality, though Des Cartes and some others use this mark, ∝: thus, a=b signifies that a is equal to b. Others use the mark = to denote identity of ratios.
× into or with. The sign of multiplication, showing that the quantities on each side the same are to be multiplied by one another: as, a×b is to be read, a multiplied into b; 4×8, the product of 4 multiplied into 8. Wolfius and others use a dot between the two factors: thus, 7·4 signifies the product of 7 and 4. In algebra the sign is commonly omitted, and the two quantities put together: thus, bd expresses the product of b and d. When one or both of the factors are compounded of several letters, they are distinguished by a line drawn over them: thus, the factum of a+b-c into d is written, d × a̅+̅b̅-̅c̅. Others distinguish the compound factors by including them in parentheses: thus, (a+b-c)d.
÷ by. The sign of division: thus, a÷b denotes the quantity a to be divided by b. Wolfius makes the sign of division two dots; 12:4 denotes the quotient of 12 divided by 4 = 3.
> or ⫍ are signs of majority: thus, a>b expresses that a is greater than b.