What will be the sum of the first (68) natural numbers?
Answer and explanation
Correct answer: 2346
The sum of the first \(n\) natural numbers is \(S_n=\frac{n(n+1)}{2}\). Therefore, \(S_{68}=\frac{68\times69}{2}=34\times69=2346\). Hence, 2346 is correct. A value such as 2356 can result from an error in multiplication or addition. Exam tip: when \(n\) is even, divide \(n\) by 2 first to calculate quickly.
Frequently asked questions
What is the correct answer to this question?
2346
Why is this the correct answer?
The sum of the first \(n\) natural numbers is \(S_n=\frac{n(n+1)}{2}\). Therefore, \(S_{68}=\frac{68\times69}{2}=34\times69=2346\). Hence, 2346 is correct. A value such as 2356 can result from an error in multiplication or addition. Exam tip: when \(n\) is even, divide \(n\) 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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