How much is the sum of the first (12) natural numbers?
Answer and explanation
Correct answer: 78
The sum of the first \(n\) natural numbers is \(S_n=\frac{n(n+1)}{2}\). Substituting \(n=12\), \(S_{12}=\frac{12\times13}{2}=6\times13=78\). Therefore, 78 is the correct answer. A value such as 72 may result from using an incorrect multiplication or average. Exam tip: in such questions, use \(n(n+1)/2\) and divide the even factor by 2 before multiplying.
Frequently asked questions
What is the correct answer to this question?
78
Why is this the correct answer?
The sum of the first \(n\) natural numbers is \(S_n=\frac{n(n+1)}{2}\). Substituting \(n=12\), \(S_{12}=\frac{12\times13}{2}=6\times13=78\). Therefore, 78 is the correct answer. A value such as 72 may result from using an incorrect multiplication or average. Exam tip: in such questions, use \(n(n+1)/2\) and divide the even factor by 2 before multiplying.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Sequences and Progressions. Topic: Sum of first n natural numbers.
