Number Sequence Practice
Number-series pattern recognition. Today's free drill comes from a fixed 180-day pool. No signup. Runs in your browser.
15 questions · 3 minutes · today's set
Arithmetic, geometric, quadratic, Fibonacci-like and alternating-step sequences. +1 per correct answer, −1 per wrong answer, skips are free. Everyone gets the same 15 questions today.
Five sequence patterns
Each question shows a few terms and asks for the next one. Questions come from five pattern families, each with its own tell:
| Arithmetic | Constant difference between terms: 4, 7, 10, 13, → next is 16 (+3 each step). |
|---|---|
| Geometric | Constant ratio between terms: 3, 6, 12, 24, → next is 48 (×2 each step). |
| Quadratic-feel | The gaps between terms grow by a constant amount: 1, 2, 4, 7, → next is 11 (the gaps themselves are 1, 2, 3, 4). |
| Fibonacci-like | Each term is the sum of the previous two: 2, 3, 5, 8, → next is 13. |
| Alternating-step | Two step sizes alternate: 5, 8, 6, 9, → next is 7 (+3, −2, +3, −2, …). |
Why pattern recognition shows up in quant OAs
Firms rarely label a section "sequences," but "what comes next" items are common in the numerical and logical-reasoning tests used early in the process. CTC's online assessment, for example, mixes numerical reasoning with spatial, verbal and logic reasoning. The Realistic OA Trial is a full-length practice version of that format. Fermi estimates and brain teasers test the same skill: finding the rule behind a few data points quickly, without being told what kind of rule to look for.
Probability & EV practice
Probability has its own daily drill: Probability & EV Practice. For both skills in one test, take the 60-question Sequences & Probability test.
Related practice
- Realistic OA Trial: CTC-style, numerical/spatial/verbal/logic mixed
- Mental Math Practice: arithmetic speed drills and firm-specific formats
- How to prepare for a quant trading interview: the full pipeline and a study plan
Questions
What kinds of sequences are in the daily drill?
15 questions in 3 minutes, mixing arithmetic (constant difference), geometric (constant ratio), quadratic-feel (constant second difference), Fibonacci-like (each term is the sum of the previous two), and alternating-step patterns. Each question is generated by iterating its rule, so the next term is always correct.
What's a good score on this drill?
11 of 15 is a reasonable target. This is a daily practice drill, so there is no firm cutoff or official pass mark. Once you score above that consistently, move on to the app's full-length firm formats.
How do I get faster at spotting the pattern?
Always compute the differences between consecutive terms before guessing a named sequence. Arithmetic and geometric patterns show up in that first row of differences (or ratios). Quadratic-feel patterns show up one row down, in the differences of the differences. Only try Fibonacci-like or alternating-step once constant difference and constant ratio are ruled out. Checking in that order is faster than pattern-matching from memory.
Why is this separate from probability & EV now?
They are different skills: pattern recognition in a series, and probability and expected-value calculation. An older test combined them only because both are generic firm-test formats. This page covers sequences only. Probability has its own Daily Probability & EV drill.
Is there a longer, combined version?
Yes. The original 60-question Sequences & Probability test mixes both skills in one full-length fixed set. This daily drill is shorter, covers sequences only and rotates every day.