Guided Mode
Step-by-step Gaussian elimination with highlighted cells, guided prompts, and feedback on every move.
The Elimination Game
step 1 misses 0
- Decide whether a matrix is in row echelon form.
- Choose the next row operation: pivot, scale, or clear.
- Reduce an augmented matrix to REF with elementary row operations.
- Identify basic and free variables from the pivot columns.
- Determine whether a system has no solutions, exactly one, or infinitely many.
This course uses leading 1s in REF.
- Zero rows are at the bottom.
- Each nonzero row starts with a leading 1.
- Leading 1s move strictly right as you go down.
- Entries below each leading 1 are zero.
| 1 | 2 | −1 | 4 |
| 0 | 1 | 3 | −2 |
| 0 | 0 | 1 | 5 |
- Variables: Variables in coefficient pivot columns are basic; the other variables are free.
- Solutions: a contradiction means none; otherwise no free variables means unique, and any free variable means infinitely many.
Choose a mode
Independent Mode
Follow the same pivot–scale–clear route without highlighted cells or step-by-step prompts.
10 quick questions
Warm-up: is it REF?
Question 1 of 10 Score 0/10
Is this matrix in row echelon form?
Scroll to see all columns.
Swipe left or tap Next Matrix.
Warm-up complete
★★★
Score: 0/10
Best: 0/10
Start
Choose the next step in this elimination route.
Pick an answer.
Scroll to see all columns.
System as equations
Use Left and Right Arrow to read the full expression.
Puzzle complete
★★★
Misses0
Return to the menu?
Your current puzzle will be paused so you can resume it later.
About The Elimination Game
Version: The Elimination Game [v0.4(beta)]
Copyright: © 2026 Sébastien Roch
Code license: The software source code—including the functional HTML, CSS, and JavaScript—is available under the MIT License.
Content license: Except where otherwise noted, the original instructional text, questions, feedback, and visual assets are licensed under the Creative Commons Attribution-NonCommercial 4.0 International License.
Textbook: math345-textbook.github.io
Privacy: Your best scores are saved in this browser on this device. They are not uploaded anywhere. If you use a private window, clear site data, switch browsers, or block site storage, your best scores may reset.
Acknowledgments: Thanks to Betsy Stovall and Jingyi Li for helpful feedback.