A constant is a term that does not change.

In the expression 2x + 3 there are two terms, "2x" and "3".

Since the term "2x" contains the variable "x", "2x" is NOT a constant term.

Since the term "3" contains no variables, "3" IS a constant term.

In the expression 2x - 5 the constant term is -5.

In the expression -5 + 4y the constant term is -5.

In the expression 3x + 5 + 9y the constant term is 5.

In the expression 3x + π the constant term is π.

In science, a constant is a value (measured or calculated) that never changes.

The value of pi (the ratio of the circumference of a circle to the radius of the circle).

The factor used to convert inches to centimetres (multiply the number of inches by 2.54 cm/in).