Chapter 1: Series Completion

Introduction

Series Completion is a foundational topic in Aptitude Questions for Competitive Exams, testing a candidate’s logical reasoning and pattern recognition skills. It focuses on identifying the rule or relationship that defines the arrangement of numbers, letters, or figures and predicting the missing or next term. This chapter not only measures intelligence but also the ability to think sequentially — a vital skill for banking, SSC, railway, and government exams.

Every competitive test features at least a few questions from this topic because it’s simple to frame yet tricky to solve without strong observation. Candidates must detect numerical progressions, alternating arrangements, or symbolic connections within a short span of time. Regular practice of series problems helps improve accuracy and boosts reasoning speed, giving aspirants an edge in the exam.

Types of Questions Asked

Number Series:
These are numerical sequences based on arithmetic or geometric patterns. For instance, “2, 4, 8, 16, ?” follows a ×2 rule. Common subtypes include addition/subtraction series, prime numbers, square/cube numbers, and mixed logic series.
Alphabet Series:
Alphabet-based sequences follow the English letter order. Example: A, D, G, J, ? (adding +3 each time). Aspirants must memorize letter positions and identify jumps or reversals.
Mixed Series:
A combination of letters, numbers, or symbols like A1, B2, C3… where two or more logics apply simultaneously.
Figure Series:
In non-verbal reasoning, visual figures form a sequence based on rotation, reflection, or shading patterns.