pound
Is a number sentence that does not equal anything or has an equal sign.
Equation
An expression does not contain an equality sign.
A number sentence that equals or that has an equal sign.
The answer, the solution.
An equation.
pi is an irrational number that is approximately equal to 3.14
a number sentence contains an equal sign
It's called an expression!! An expression has no meaning because it has no equal sign. ex: a*b
All positive numbers are equal to their positives. Also, the absolute value of a number is the number ignoring the sign (and thus equal to the positive value of the number). eg |-1| = 1.
EQUATION
5+101=106