Write in interval notation: x 11

(-infinity, -1) or (11, infinity)

Write in interval notation: x 3

(-infinity, -7) or (3, infinity)

Write in interval notation: x 19

(-infinity, 7) or (19, infinity)

Write in interval notation: x 26

(-infinity, 13) or (26, infinity)

Write in interval notation: x -2

(-infinity, -12) or (-2, infinity)

Write in interval notation: x 14

(-infinity, 0) or (14, infinity)

Write in interval notation: x 28

(-infinity, 14) or (28, infinity)

Worksheets · Precalculus

Precalculus interval notation worksheet

Q: Are these interval notation worksheets free?

Yes. Every interval notation sheet is free to print and free to download as a PDF. There is no account to make, no email to hand over and no limit on how many you take.

Q: Do the interval notation worksheets come with an answer key?

Yes. The answer key prints on a second page, and you can choose whether it shows each question beside its answer or just the answers in a list.

Q: Are these interval notation worksheets printable?

Yes. Print straight from the page, or download the PDF and print that. The sheet is laid out for paper rather than squeezed off a screen, so there is room to work under each question, and the answer key comes out on its own page.

Q: What grade are these interval notation worksheets for?

Precalculus is usually taken around 11th or 12th grade, though schools vary and plenty of students meet it earlier or later. Pick the difficulty rather than the grade: the easy level suits a first lesson on it, the hard level suits review before a test.

Q: Can I get a different version of the same interval notation worksheet?

Yes, as many as you like. The questions are built fresh each time rather than picked from a fixed set of files, so pressing Generate gives a new sheet. That is what you want for a second class, a retake, or two students sitting next to each other.

Q: Is this a free alternative to Kuta Software for interval notation?

That is the closest comparison, and Kuta Software is good software. It is also paid software you install on a computer. These worksheets run in a browser tab for free, with no account and nothing to install. Like Kuta, the interval notation questions are generated when you ask for them rather than pulled from a fixed set of files, so two classes never get the same sheet, and the answer key comes with it.

Q: Can I choose how hard the interval notation questions are?

Yes. There are three levels, and you can tick more than one for a sheet that mixes them, in which case the questions come out easiest first. The harder levels are not just larger numbers: they ask for something the easy ones do not.

Q: What do students get wrong with interval notation?

Using a square parenthesis against infinity. It is never included, so it always takes a round one. The other slip is reversing the order: the smaller number always comes first.

A square parenthesis means the endpoint is included and a round one means it is not. Infinity always gets a round parenthesis, because you never reach it.

Select your difficulty

Pick more than one for a sheet that mixes them.



Sigma Prep · sigmaprep.io/worksheets Name Interval Notation Date Period Write each in interval notation. Write in interval notation: $15 \leq x < 29$ Write in interval notation: $x < - 1$ or $x > 11$ Write in interval notation: $x \geq - 11$ Write in interval notation: $x < - 7$ or $x > 3$ Write in interval notation: $9 \leq x < 20$ Write in interval notation: $x \geq 7$ Write in interval notation: $x \geq 8$ Write in interval notation: $x > - 11$ Write in interval notation: $x < - 14$ Write in interval notation: $x < 7$ or $x > 19$ Write in interval notation: $x < 13$ or $x > 26$ Write in interval notation: $x < - 12$ or $x > - 2$ Write in interval notation: $x < 0$ or $x > 14$ Write in interval notation: $14 < x \leq 24$ Write in interval notation: $x < - 5$ Write in interval notation: $x > 10$ Write in interval notation: $x \leq 12$ Write in interval notation: $- 5 \leq x \leq 5$ Write in interval notation: $- 12 < x \leq 0$ Write in interval notation: $x < 14$ or $x > 28$ Free math worksheets at sigmaprep.io/worksheets© 2026 Sigma Prep

Sigma Prep · sigmaprep.io/worksheets

Name

Interval Notation

Date Period

Write each in interval notation.

Write in interval notation: $15 \leq x < 29$
Write in interval notation: $x < - 1$ or $x > 11$
Write in interval notation: $x \geq - 11$
Write in interval notation: $x < - 7$ or $x > 3$
Write in interval notation: $9 \leq x < 20$
Write in interval notation: $x \geq 7$
Write in interval notation: $x \geq 8$
Write in interval notation: $x > - 11$
Write in interval notation: $x < - 14$
Write in interval notation: $x < 7$ or $x > 19$
Write in interval notation: $x < 13$ or $x > 26$
Write in interval notation: $x < - 12$ or $x > - 2$
Write in interval notation: $x < 0$ or $x > 14$
Write in interval notation: $14 < x \leq 24$
Write in interval notation: $x < - 5$
Write in interval notation: $x > 10$
Write in interval notation: $x \leq 12$
Write in interval notation: $- 5 \leq x \leq 5$
Write in interval notation: $- 12 < x \leq 0$
Write in interval notation: $x < 14$ or $x > 28$



Sigma Prep · sigmaprep.io/worksheets Name Interval NotationAnswer keyVersion 1 Date Period Write each in interval notation. Write in interval notation: $15 \leq x < 29$ $[15, 29)$ Write in interval notation: $x < - 1$ or $x > 11$ $(- \infty, - 1) \cup (11, \infty)$ Write in interval notation: $x \geq - 11$ $[- 11, \infty)$ Write in interval notation: $x < - 7$ or $x > 3$ $(- \infty, - 7) \cup (3, \infty)$ Write in interval notation: $9 \leq x < 20$ $[9, 20)$ Write in interval notation: $x \geq 7$ $[7, \infty)$ Write in interval notation: $x \geq 8$ $[8, \infty)$ Write in interval notation: $x > - 11$ $(- 11, \infty)$ Write in interval notation: $x < - 14$ $(- \infty, - 14)$ Write in interval notation: $x < 7$ or $x > 19$ $(- \infty, 7) \cup (19, \infty)$ Write in interval notation: $x < 13$ or $x > 26$ $(- \infty, 13) \cup (26, \infty)$ Write in interval notation: $x < - 12$ or $x > - 2$ $(- \infty, - 12) \cup (- 2, \infty)$ Write in interval notation: $x < 0$ or $x > 14$ $(- \infty, 0) \cup (14, \infty)$ Write in interval notation: $14 < x \leq 24$ $(14, 24]$ Write in interval notation: $x < - 5$ $(- \infty, - 5)$ Write in interval notation: $x > 10$ $(10, \infty)$ Write in interval notation: $x \leq 12$ $(- \infty, 12]$ Write in interval notation: $- 5 \leq x \leq 5$ $[- 5, 5]$ Write in interval notation: $- 12 < x \leq 0$ $(- 12, 0]$ Write in interval notation: $x < 14$ or $x > 28$ $(- \infty, 14) \cup (28, \infty)$ Free math worksheets at sigmaprep.io/worksheets© 2026 Sigma Prep

Sigma Prep · sigmaprep.io/worksheets

Name

Interval NotationAnswer keyVersion 1

Date Period

Write each in interval notation.

Write in interval notation: $15 \leq x < 29$ $[15, 29)$
Write in interval notation: $x < - 1$ or $x > 11$ $(- \infty, - 1) \cup (11, \infty)$
Write in interval notation: $x \geq - 11$ $[- 11, \infty)$
Write in interval notation: $x < - 7$ or $x > 3$ $(- \infty, - 7) \cup (3, \infty)$
Write in interval notation: $9 \leq x < 20$ $[9, 20)$
Write in interval notation: $x \geq 7$ $[7, \infty)$
Write in interval notation: $x \geq 8$ $[8, \infty)$
Write in interval notation: $x > - 11$ $(- 11, \infty)$
Write in interval notation: $x < - 14$ $(- \infty, - 14)$
Write in interval notation: $x < 7$ or $x > 19$ $(- \infty, 7) \cup (19, \infty)$
Write in interval notation: $x < 13$ or $x > 26$ $(- \infty, 13) \cup (26, \infty)$
Write in interval notation: $x < - 12$ or $x > - 2$ $(- \infty, - 12) \cup (- 2, \infty)$
Write in interval notation: $x < 0$ or $x > 14$ $(- \infty, 0) \cup (14, \infty)$
Write in interval notation: $14 < x \leq 24$ $(14, 24]$
Write in interval notation: $x < - 5$ $(- \infty, - 5)$
Write in interval notation: $x > 10$ $(10, \infty)$
Write in interval notation: $x \leq 12$ $(- \infty, 12]$
Write in interval notation: $- 5 \leq x \leq 5$ $[- 5, 5]$
Write in interval notation: $- 12 < x \leq 0$ $(- 12, 0]$
Write in interval notation: $x < 14$ or $x > 28$ $(- \infty, 14) \cup (28, \infty)$

How to do these

Write in interval notation: $- 2 < x \leq 5$

-2 is not included, so a round parenthesis.
5 is included, so a square parenthesis.

The answer is $(- 2, 5]$ .

Where students go wrong

Using a square parenthesis against infinity. It is never included, so it always takes a round one. The other slip is reversing the order: the smaller number always comes first.

Also called writing intervals, set notation or parenthesis and parenthesis notation.

Questions about these worksheets