Which is the sum of the first (28) natural numbers?
Answer and explanation
Correct answer: 406
The sum of the first \(n\) natural numbers is \(\frac{n(n+1)}{2}\). Substituting \(n=28\), we get \(\frac{28\times29}{2}=14\times29=406\). Although 396 is close, it is not obtained by correctly dividing \(28\times29\) by 2. Exam tip: Divide the even factor by 2 first to calculate quickly.
Frequently asked questions
What is the correct answer to this question?
406
Why is this the correct answer?
The sum of the first \(n\) natural numbers is \(\frac{n(n+1)}{2}\). Substituting \(n=28\), we get \(\frac{28\times29}{2}=14\times29=406\). Although 396 is close, it is not obtained by correctly dividing \(28\times29\) by 2. Exam tip: Divide the even factor by 2 first to calculate quickly.
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.
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