Practice Constant vs Variable in Math

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

Constants are symbols with fixed, unchanging values; variables are symbols whose values can change or are yet to be determined.

π≈3.14159 is always the same (constant). x can be anything (variable).

Showing a random 20 of 50 problems.

Example 1

challenge
In the equation ax+b=0 with a≠0 constant and b constant, give a formula for the variable x.

Example 2

medium
In y=mx+b, which symbols are parameters once a specific line is chosen?

Example 3

easy
In 9−2x, list the constants.

Example 4

medium
In A=πr2, classify each symbol.

Example 5

challenge
In y=asin⁡(bx+c)+d, classify each symbol if you study one specific sine curve.

Example 6

easy
In y=7, can y vary?

Example 7

medium
In P=4s for a square, classify P, s, and 4.

Example 8

easy
Is the speed of light c a constant or variable in physics?

Example 9

challenge
In f(x)=c for an unknown constant c, what is the rate of change of f, and what is f(100)−f(7)?

Example 10

easy
In 7y−4, identify the variable.

Example 11

easy
In 3x+5, name the constants.

Example 12

easy
In 2r, if r is a length that can change, what is r?

Example 13

medium
In a chemistry formula PV=nRT, identify the constant.

Example 14

easy
In C=2πr, identify the constants and variables.

Example 15

easy
In V=lwh, classify each symbol if a box's dimensions can change.

Example 16

challenge
In y=ax+b, explain why a and b are constants for one line yet behave like variables across the family of all lines.

Example 17

hard
Given y=kx with k a fixed proportionality constant. If (x,y)=(4,12) lies on this graph, find k and then y when x=9.

Example 18

medium
A letter c is a constant in E=mc2 but a variable in y=cx. Explain in one line.

Example 19

easy
Is π a constant or a variable?

Example 20

medium
In h(x)=3, what is the rate of change of the output?