Natural Number

All positive whole numbers, not including zero.
Examples: 4, 7, 9

Negative Slope

The slope of a line is negative if the line runs from the top left to the bottom right. The moves for the slope should be opposite moves, either down and to the right or up and to the left.

No Solution

Used when solving an equation in which the solution of the equation is false. No solution means that there is not possible value for x that would make the equation true.

Numerical Expression

A number or a group of numbers that are added, subtracted, multiplied, or divided.
Example: 4 + 6 is a numerical expression.