Series - Number & Alphabet
A series is a sequence of numbers or letters that follow a specific, logical rule. In competitive exams like the UPSC, these questions test your ability to identify hidden patterns quickly. There are mainly three types of series: Number Series, Alphabet Series, and Mixed Series. A Number Series involves digits arranged based on mathematical operations like addition, multiplication, or squares. An Alphabet Series uses letters from A to Z, often based on their position numbers.
Concepts (3)
Number series follow rules like addition, subtraction, multiplication, or division. Some series use squares (n²) or cubes (n³). A common type is the 'Arithmetic Progression' where the same number is added every time.
Number series follow rules like addition, subtraction, multiplication, or division. Some series use squares (n²) or cubes (n³). A common type is the 'Arithmetic Progression' where the same number is added every time. Another is the 'Geometric Progression' where terms are multiplied. Example: In the series 2, 4, 8, 16, the rule is 'multiply by 2'. In 10, 13, 16, 19, the rule is 'add 3'. Always look for the change between numbers first.
Letters are assigned numbers from 1 to 26 (A=1 to Z=26). Questions often use these values to create patterns. For example, 'A, C, E, G' is actually '1, 3, 5, 7' which is a series of odd numbers. Sometimes letters are used in reverse (Z=1, Y=2).
Letters are assigned numbers from 1 to 26 (A=1 to Z=26). Questions often use these values to create patterns. For example, 'A, C, E, G' is actually '1, 3, 5, 7' which is a series of odd numbers. Sometimes letters are used in reverse (Z=1, Y=2). To find the reverse position of any letter, subtract its forward position from 27. Example: Position of 'D' is 4. Its reverse position is 27 - 4 = 23 (which is 'W').
These are long strings of letters with missing blanks, like 'ab_bc_c_a'. To solve these, count the total length. If there are 12 characters, try dividing them into groups of 3 or 4. Look for a repeating 'block' of letters.
These are long strings of letters with missing blanks, like 'ab_bc_c_a'. To solve these, count the total length. If there are 12 characters, try dividing them into groups of 3 or 4. Look for a repeating 'block' of letters. In the example 'abab_b_bc', the block might be 'abc'. By placing 'c' and 'a' in the blanks, you complete the cycle. This tests your ability to see patterns in a crowded string.
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Start Lesson: Number Series Patterns