Every year, thousands of aspirants chase the SBI PO dream, but only those who master speed and accuracy in Quantitative Aptitude truly stand out. Among the trickiest yet most rewarding topics is the Missing Number Series. It looks simple at first glance, but examiners design patterns that test your intuition, calculation speed, and ability to spot hidden logic. In this blog, we’ll uncover the Top 40 Missing Number Series types with examples, strategies, and practice insights that can transform your preparation.
Missing Number Series questions demand sharp observation and quick recognition of mathematical patterns. From cubes and squares to prime differences and alternating multiplications, these series cover a wide range of logic.
Below, we break down the Top 40 types with examples to help you solve them in under 30 seconds.
Cubes are one of the most common foundations of missing number series. Examiners love to test whether aspirants can quickly spot consecutive cube values hidden in a sequence. Recognizing these instantly saves precious seconds in the exam.
Example: 8, 27, 64, ?
Logic: Consecutive cubes ($2^3$, $3^3$, $4^3$).
Answer: 125 ($5^3$).
Prime numbers often sneak into series as multipliers. When combined with a base like 6 or 8, they create tricky progressions. Spotting prime multiples early ensures you don’t waste time chasing random differences.
Example: 18, 30, 42, 66, ?
Logic: Multiples of 6 with prime factors (6×3, 6×5, 6×7…).
Answer: 78.
Incremental differences are a favorite examiner trick. They start small and grow steadily, forcing you to notice the pattern of addition. Missing this can derail your speed, so train your eyes to catch it fast.
Example: 5, 8, 14, 23, ?
Logic: Differences of +3, +6, +9.
Answer: 35.
Perfect squares often appear as hidden add‑ons in series. If you can connect terms to square values, the sequence becomes clear. This pattern rewards those who revise squares thoroughly before the exam.
Example: 4, 68, 168, ?
Logic: Adding consecutive squares ($2^2$, $8^2$, $10^2$).
Answer: 34.
Sometimes the difference between terms follows prime numbers. This subtle twist makes the series harder to crack unless you’re comfortable with prime progressions. Quick recognition here can give you a scoring edge.
Example: 124, 131, 142, 155, ?
Logic: Adding prime gaps (7, 11, 13…).
Answer: 172.
Multiplication tables are a hidden weapon in missing series. Examiners often disguise them with larger bases like 16, expecting aspirants to overlook the obvious. Spotting them quickly is a huge time saver.
Example: 16, 32, 48, ?
Logic: Multiplication table of 16.
Answer: 64.
Unit digits can confirm or break your guess. Many series rely on multiplication where the unit digit reveals the next term. Training in this technique builds confidence and accuracy under pressure.
Example: 12, 36, 108, ?
Logic: Multiplication with unit digit checks.
Answer: 324.
Series often mix decreasing and increasing multipliers to confuse aspirants. Recognizing the shift in direction is key. Once spotted, the logic flows smoothly, and the answer falls into place.
Example: 128, 640, 1280, ?
Logic: Multiply by 5, then double, then multiply by 4.
Answer: 3584.
Alternating operations are a clever twist. Multiplication followed by division creates a rhythm that only sharp observation can catch. Missing this rhythm leads to wasted time and wrong answers.
Example: 9, 45, 7.5, 37.5, ?
Logic: ×5, ÷6 alternately.
Answer: 45.
Simple multiplication tables often hide in plain sight. Examiners expect aspirants to overlook them under exam stress. Recognizing these instantly can give you quick marks with minimal effort.
Example: 40, 48, 56, ?
Logic: Multiples of 8 (8×5, 8×6…).
Answer: 64.
Adding consecutive integers is a straightforward but effective trick. It tests whether aspirants can extend a simple addition sequence without overthinking. Quick spotting here ensures easy scoring.
Example: 70, 73, 77, ?
Logic: Add 3, 4, 5…
Answer: 82.
Products of consecutive numbers create elegant series. They look complex but follow a clear multiplication logic. Recognizing this saves time and builds confidence in tackling tougher series.
Example: 12, 20, 30, 42, ?
Logic: 3×4, 4×5, 5×6, 6×7…
Answer: 56.
Example: 3, 7, 15, 31, ?
Logic: Double the previous term and add 1.
Answer: 63.
Example: 1, 2, 6, 24, ?
Logic: Factorials (1!, 2!, 3!, 4!).
Answer: 120 (5!).
Example: 2, 3, 5, 8, 13, ?
Logic: Fibonacci sequence.
Answer: 21.
Example: 0, 3, 8, 15, ?
Logic: (n^2 – 1).
Answer: 24.
Example: 3, 9, 27, ?
Logic: Multiply by 3 each time.
Answer: 81.
Example: 2, 6, 12, 20, ?
Logic: Add consecutive even numbers.
Answer: 30.
Example: 4, 9, 25, 49, ?
Logic: Squares of primes (2², 3², 5², 7²…).
Answer: 121 (11²).
Example: 256, 128, 64, ?
Logic: Divide by 2 each step.
Answer: 32.
Example: 10, 15, 12, 17, ?
Logic: +5, −3 alternately.
Answer: 14.
Example: 21, 13, 8, 5, ?
Logic: Fibonacci backwards.
Answer: 3.
Example: 2, 4, 12, 48, ?
Logic: Multiply by 2, 3, 4…
Answer: 240.
Example: 1, 4, 9, 16, ?
Logic: Perfect squares.
Answer: 25.
Example: 1, 3, 6, 10, ?
Logic: Sum of consecutive integers.
Answer: 15.
Example: 7, 26, 63, ?
Logic: (n^3 – 1).
Answer: 124.
Example: 11, 22, 33, ?
Logic: Table of 11.
Answer: 44.
Example: 2, 4, 8, 10, 20, ?
Logic: ×2, +2 alternately.
Answer: 22.
Example: 2, 5, 10, 17, ?
Logic: Add consecutive primes (3, 5, 7…).
Answer: 26.
Example: 5, 13, 29, ?
Logic: Square numbers plus primes.
Answer: 53.
Example: 9, 18, 27, ?
Logic: Table of 9.
Answer: 36.
Example: 3, 5, 9, 17, ?
Logic: Differences are squares (2, 4, 8…).
Answer: 33.
Example: 2, 6, 18, 54, ?
Logic: ×3 each time.
Answer: 162.
Example: 64, 32, 96, 48, ?
Logic: ÷2, ×3 alternately.
Answer: 144.
Example: 2, 5, 10, 17, ?
Logic: (n^2 + 1).
Answer: 26.
Example: 8, 27, 125, ?
Logic: Cubes of primes (2³, 3³, 5³…).
Answer: 343 (7³).
Example: 10, 13, 17, 22, ?
Logic: +3, +4 alternately.
Answer: 26.
Example: 4, 6, 9, 13.5, ?
Logic: ×1.5 each time.
Answer: 20.25.
Example: 3, 7, 21, 43, ?
Logic: Square numbers minus primes.
Answer: 73.
Example: 2, 3, 5, 9, 17, ?
Logic: Double previous term −1.
Answer: 33.
Mastering Missing Number Series isn’t just about knowing patterns — it’s about solving them under exam pressure. PracticeMock’s SBI PO mock tests replicate the exact exam environment, pushing you to solve series in 15–30 seconds. With detailed solutions, performance analytics, and timed practice, you’ll sharpen both speed and accuracy. The best way to test your current preparation is to attempt a free mock test today. It will instantly show where you stand and which series types need more revision.
Missing Number Series questions are a scoring opportunity in SBI PO 2026 if you prepare smartly. By practicing the Top 40 types, analyzing differences, cubes, primes, and alternating operations, you’ll build the intuition needed to crack them quickly. Pair this with regular mock test practice, and you’ll be ready to face any tricky series the exam throws at you.
Missing Number Series are logical sequences where candidates must identify the missing term using mathematical patterns.
Typically 4–5 questions in the Quant section, but they carry high scoring potential if solved quickly.
Revise cubes, squares, prime differences, and alternating operations. Attempt mock tests to build speed and accuracy.
Yes, they test advanced pattern recognition and logical reasoning, making them crucial for both Prelims and Mains.
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