Practice Irrational Numbers in Math

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

Quick Recap

An irrational number is a real number that cannot be expressed as a ratio of two integers pq; its decimal expansion goes on forever without repeating any fixed block of digits.

π and 2 go on forever without any pattern—you can't write them as a fraction.

Showing a random 20 of 50 problems.

Example 1

challenge
Prove that 2 is irrational (outline the contradiction).

Example 2

easy
Is 2 rational or irrational?

Example 3

hard
Is the set of irrationals closed under addition?

Example 4

easy
Is 25 rational or irrational?

Example 5

medium
Classify each: 0.04, 0.5.

Example 6

medium
Order from least to greatest: 8,3,π.

Example 7

medium
Rationalize and classify 12.

Example 8

medium
Order from least to greatest: 2, 1.5, 3.

Example 9

medium
Is 182 rational or irrational?

Example 10

easy
Is 11 rational or irrational?

Example 11

medium
Give an example of an irrational number between 1.1 and 1.2.

Example 12

medium
Simplify 72 and classify it.

Example 13

challenge
Show that 2+3 is a root of a polynomial with integer coefficients; what is its minimal polynomial?

Example 14

easy
Is 49+3 rational or irrational? Explain.

Example 15

easy
Between which two consecutive integers does 19 lie?

Example 16

medium
Show that 2 lies between 1.4 and 1.5, then estimate it to one decimal place.

Example 17

medium
Prove that 3 is irrational by contradiction.

Example 18

medium
Give an example of two irrational numbers whose sum is rational.

Example 19

medium
Is 2⋅π rational or irrational?

Example 20

medium
Simplify 50 and state whether it is rational.