OTHER SIGNS USED IN ALGEBRA.

12. The Sign of Equality, $=$.

The sign $=$ is read is equal to, when placed between two numbers and indicates that these two numbers are equal.

Thus, $8+4=12$ means that $8+4$ and $12$ stand for equal numbers; $x+y=20$ means that $x+y$ and $20$ stand for equal numbers.

13. The Sign of Inequality, $>$ or $<$.

The sign $>$ or $<$ is read is greater than and is less than respectively, and when placed between two numbers indicates that these two numbers are unequal, and that the number toward which the sign opens is the greater.

Thus, $9+6>12$ means that $9+6$ is greater than $12$; and $9+6<16$ means that $9+6$ is less than $16$.

14. The Sign of Deduction, $$

The sign $\therefore$ is read hence or therefore.

15. The Sign of Continuation, $$.

The sign $\dots$ is read and so on.

16. The Signs of Aggregation.

The signs of aggregation are the bar $|$, the vinculum $\overline{\phantom{a+x}}$, the parenthesis $()$, the bracket $[]$, and the brace $\{\}$.

Thus, each of the expressions $$\begin{gathered} ra \\ +b| \end{gathered}$$, $\overline{a+b\phantom{(}}$, $(a+b)$, $[a+b]$, $\{a+b\}$, signifies that $a+b$ is to be treated as a single number.