# 2 5 9 - 20 35 Easy Missing number Math Riddle

Sequences can be intriguing puzzles that challenge our pattern recognition skills. Today, we're diving into a sequence that starts with 2 and then progresses to 5, 9, 14, 20, with a missing number, and finally reaches 35. The question is simple: What's the missing number in this sequence? Join us as we uncover the pattern, explain the math, and arrive at the answer step by step.

What is the missing number in the sequence 2, 5, 9, 14, 20, ?, 35

Explanation :

Let's define the sequence as S(n), where "n" is the position in the sequence.

S(1) = 2

To find the pattern, you correctly observed the following:

S(n) = S(n-1) + n + 1

This equation represents the mathematical pattern where each term in the sequence is obtained by adding the previous term (S(n-1)) to the position in the sequence (n) plus 1. This is why we have:

• S(1) = S(1-1) + 1 + 1 = 2
• S(2) = S(2-1) + 2 + 1 = 5
• S(3) = S(3-1) + 3 + 1 = 9
• S(4) = S(4-1) + 4 + 1 = 14
• S(5) = S(5-1) + 5 + 1 = 20
• S(6) = S(6-1) + 6 + 1 = 27
• S(7) = S(7-1) + 7 + 1 = 35

So, using this pattern, we can find the missing number in the sequence:

S(6) = S(6-1) + 6 + 1 = S(5) + 7 = 20 + 7 = 27

The missing number is 27, and the sequence follows the pattern you've described.