Order check.
AskSia identifies whether order matters in the problem to pick the right formula.
Identification
EN
Permutation and Combination Solver
Permutations and combinations, counted exactly.
Type or photograph the counting problem. AskSia identifies whether order matters (permutation) or not (combination), applies the right formula, and shows the arithmetic.
Works with word problems, equations, code, and science prompts.
∫ 3x² · sin(x) dx
SubjectsCalculusAlgebraPhysicsChemistryBiologyCSStatisticsEcon
4.9 / 5 · trusted by 2M+ students · 50M+ problems solved
asksia.ai/solver
98% · Verified
Problem
Find the area enclosed between y = x² and y = 2x in the first quadrant.
1
Find the points of intersection
Set the curves equal: x² = 2x → x(x - 2) = 0, so x = 0 and x = 2.
2
Identify which curve is on top
On (0, 2), 2x > x², so y = 2x is the upper curve.
3
Set up the area integral
A = ∫₀² (2x - x²) dx
4
Integrate term-by-term
A = [ x² - x³/3 ]₀²
Final Answer
A = 4/3 sq. units
Quick Answer
What is the difference between permutations and combinations?
A permutation is an ordered arrangement of r items chosen from n, counted as P(n, r) equals n factorial divided by (n minus r) factorial. A combination is an unordered selection of r items chosen from n, counted as C(n, r) equals n factorial divided by r factorial times (n minus r) factorial. Use permutations when the order matters (lineups, sequences, rankings). Use combinations when only the selection matters (committees, hands of cards, subsets). Combinations are smaller than permutations because they ignore the orderings.
98%
solution accuracy
50M+
problems solved
~1.5s
avg solve time
A+
study-ready explanations
Why AskSia Solver
Why students use AskSia for Permutation and Combination.
Every step transparent, every answer self-checked.
Formula applied.
P(n,r) or C(n,r) with factorial computations shown step by step.
Direct
Repetition handled.
If repetition is allowed, AskSia uses the right formula variant.
Variations
Plain-English check.
AskSia restates the problem in counting terms to confirm the right setup.
Verification
Photo, paste, or type.
Snap handwritten or printed problems with your phone, paste from any online homework portal, or type with full LaTeX support.
Multi-modal input
Verified by AskSia.
Every answer gets a self-check pass. Sia catches sign errors and algebra mistakes before you submit your homework.
Self-checked
How It Works
Solve any Permutation and Combination problem in three steps.
Step 01
Enter the problem.
Type the expression, paste from your homework, snap a photo, or speak it. AskSia parses your input and identifies the structure.
Input mode
Snap a Photo
Textbook, handwriting, screenshot
Paste Text
Word problem or equation
Calculator
LaTeX-ready equation editor
Step 02
AskSia picks the method.
Based on the problem structure, AskSia chooses the cleanest solution path and labels each step with the operation performed.
1
Set curves equal
x² = 2x → x = 0, x = 2
2
Set up the integral
A = ∫₀² (2x - x²) dx
3
Evaluate
A = [x² - x³/3]₀² = 4/3
Step 03
Read the verified answer.
Final result appears with a substitution or composition check. Practice problems on the same concept are one tap away.
Auto-generated diagram
Region between y = 2x and y = x² — area = 4/3
Available On
Solve anywhere
you study.
Every solve syncs across Web, iOS, and Android — start it at your desk, finish on your phone.
Web App
Full study studio
Split-panel interface with the worked solution on the left, the auto-generated diagram and AI tutor chat on the right.
Drag & drop image upload + LaTeX equation editor
Auto-generated diagrams render alongside steps
Side-panel AI tutor chat for hints and alt methods
Export to PDF, DOCX, Notion, or Google Docs
Hi! What are we studying today?
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Calculus
98% verified
1.4s
Step 4 of 4 · Evaluate
A = [x² - x³/3]₀² = 4/3
Mobile App
Snap & solve, anywhere
Open the camera, frame the problem, and the worked solution plus diagram appear in seconds.
One-tap snap-and-solve on iOS and Android
Pinch-to-zoom diagrams, swipe between steps
Auto-sync solves with your Web library
Offline review of saved solutions and flashcards
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98%
1.4s
Area between y=2x & y=x²
A = 4/3 sq. units ✓
Use Cases
What the Permutation and Combination solver covers.
Permutations of distinct objects.
Arrange n items in a row: n factorial arrangements.
Arrangement
Pick and order.
Pick r items from n and arrange them.
Pick + order
Combinations.
Subset of r items from n, order irrelevant.
Combination
With repetition.
Pick r from n with replacement: ordered or unordered variants.
Repetition
Probability questions.
Counting outcomes is the denominator (or numerator) in probability problems.
Probability
Verify your homework.
Paste your candidate answer and the original problem. AskSia walks the work, flags any divergent step, and tells you the correct final value.
Answer check
Compare
AskSia vs. ChatGPT,
Photomath & Symbolab.
General chatbots hallucinate. Photo solvers stop at math. AskSia is built for actual coursework with verified accuracy, visual learning, and every subject.
| Feature | AskSia Solver | ChatGPT | Photo Solvers |
|---|---|---|---|
| Solution accuracy | ✓ 98% | ~70-85%, hallucinations | ~90%, math only |
| Auto-generated diagrams | ✓ Every solve | Inconsistent / broken | Graphs only, math-only |
| Step-by-step explanations | ✓ Numbered + plain English | Inconsistent depth | ✓ Math steps |
| Subject coverage | ✓ Math, Physics, Chem, Bio, CS, Econ | ✓ Wide but unverified | Math only |
| Photo input | ✓ Handwriting + diagrams + code | Photos OK, weak on handwriting | ✓ Math photos only |
| Answer verification | ✓ Self-checked before display | No verification | Math engine only |
| Tutor follow-ups | ✓ Hints, alt methods, ELI5 | ✓ General chat | Not available |
| Practice and flashcards | ✓ One-tap from any solve | Manual prompting | Not available |
| Code debugging | ✓ Python, Java, C++, SQL... | ✓ Yes | Not available |
| Free to start | ✓ Daily solves, no card | Limited model access | Steps locked behind paywall |
FAQ
Frequently asked questions.
How do I know whether a problem is a permutation or combination?
Ask: does the order of selection matter? If yes (a finishing order, a code, an ordered sequence), it is a permutation. If no (a team, a committee, a subset, a hand of cards), it is a combination. Many word problems hint with words like 'arrange,' 'sequence,' 'order' (permutation) or 'choose,' 'select,' 'group,' 'committee' (combination).
Why do combinations divide by r factorial?
Because for each unordered selection of r items, there are r factorial ways to order them, and the permutation formula counts each ordering separately. Dividing the number of permutations by r factorial removes the over-counting and gives the number of distinct unordered selections.
How do you count arrangements with repeated items?
For n total items with k1 of type 1, k2 of type 2, and so on, the number of distinct arrangements is n factorial divided by k1 factorial times k2 factorial times all the other factorials. AskSia detects repeated items in the problem and applies this multinomial formula. Common example: arranging letters in 'MISSISSIPPI'.
What is 0 factorial and why?
Zero factorial is defined as 1 by convention. This makes the formulas P(n, 0) equals 1 and C(n, 0) equals 1 consistent (there is exactly one way to choose nothing). The convention 0 factorial equals 1 also makes recursion clean: n factorial equals n times (n minus 1) factorial. AskSia uses this convention throughout.
How accurate is AskSia?
AskSia hits 98% accuracy on standard high school and college coursework, measurably higher than ChatGPT, Photomath, and Symbolab on the same problem sets. Accuracy comes from subject-specialized models, a symbolic verification pass that catches arithmetic errors, and a self-check step that re-derives the answer before showing it to you.
Can I get practice problems and flashcards?
Yes. After any solve, ask Sia to generate similar practice problems at SAT, ACT, AP, IB, or college difficulty, or build a flashcard set on the underlying concept in one tap. Useful for exam prep and spaced repetition before a quiz, midterm, or final.
How much does AskSia cost?
AskSia has a free plan that includes daily solves across all subjects. AskSia Pro and Super include unlimited solves, advanced subjects, the full AI tutor companion, exports, and priority response speed. See pricing for details.
Start Today
Order or no order, factorials, the count.
Join 2M+ students using AskSia to solve permutation and combination problems step-by-step. Photo input, plain-English explanations, and a verification check on every solve.