CBSE Class 6 · Computational Thinking · 2026-27

Patterns in Mathematics: Worksheet

Skills: Pattern recognition, Abstraction, Algorithmic thinking. Circle the correct answer. Show your working in the space beside each question.

What comes next in the sequence 1, 3, 6, 10, 15, … ?
- (a) 20
- (b) 21
- (c) 22
- (d) 25
Without adding one by one, what is 1 + 3 + 5 + 7 + 9 + 11 + 13?
- (a) 42
- (b) 45
- (c) 49
- (d) 56
Matchsticks make squares in a row: 1 square uses 4 sticks, 2 squares use 7, 3 squares use 10. How many sticks for 6 squares?
- (a) 18
- (b) 19
- (c) 21
- (d) 24
What comes next: 2, 6, 18, 54, … ?
- (a) 108
- (b) 148
- (c) 162
- (d) 216
Which plan finds 1 + 2 + 3 + … + 20 fastest?
- (a) Add the numbers one at a time
- (b) Pair 1 with 20, 2 with 19, and so on: 10 pairs that each make 21
- (c) Multiply 20 × 20
- (d) Add only the even numbers and double it
A border repeats triangle, square, circle, triangle, square, circle, … What is the 20th shape?
- (a) Triangle
- (b) Square
- (c) Circle
- (d) It cannot be known

Answer key: Patterns in Mathematics

(b) 21 – 15 + 6 = 21. These are the triangular numbers.
(c) 49 – There are 7 odd numbers here, so the sum is 7 × 7 = 49.
(b) 19 – For 6 squares: 4 + 3 × 5 = 19 sticks.
(c) 162 – 54 × 3 = 162.
(b) Pair 1 with 20, 2 with 19, and so on: 10 pairs that each make 21 – 10 × 21 = 210. Breaking the sum into equal pairs is decomposition.
(b) Square – Shape 19 is a triangle and shape 20 is a square.