All formulas will have more than one variable. You need at least one independent variable and one dependent variable, so a minimum of 2.
For example, the formula for the diameter given the radius is:
d = 2r
The formula for area of a square is:
A = s²
The formula for the area of a circle is:
A = πr²
And you can have more, like the volume of a box is:
V = lwh
Or the amount of money you have with periodic compounding is:
A = P(1 + r/n)^(nt)
Answer:
More than 1