What will be the total sum of numbers from (1) to (65)?
Answer and explanation
Correct answer: 2145
The sum of the first \(n\) natural numbers is \(\frac{n(n+1)}{2}\). Here, \(n=65\), so \(\frac{65\times66}{2}=65\times33=2145\). Therefore, the correct answer is 2145. A value such as 2112 can result from using 65 or 66 incorrectly in the calculation. Exam tip: for a sum ending at \(n\), use \(\frac{n(n+1)}{2}\).
Frequently asked questions
What is the correct answer to this question?
2145
Why is this the correct answer?
The sum of the first \(n\) natural numbers is \(\frac{n(n+1)}{2}\). Here, \(n=65\), so \(\frac{65\times66}{2}=65\times33=2145\). Therefore, the correct answer is 2145. A value such as 2112 can result from using 65 or 66 incorrectly in the calculation. Exam tip: for a sum ending at \(n\), use \(\frac{n(n+1)}{2}\).
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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