How much is the sum of the first (35) natural numbers?
Answer and explanation
Correct answer: 630
The sum of the first \(n\) natural numbers is \(S_n=\frac{n(n+1)}{2}\). Therefore, \(S_{35}=\frac{35\times36}{2}=35\times18=630\). Hence, 630 is correct. Values such as 620 and 640 do not result from this formula. Exam tip: Cancel 2 with the even factor in \(n(n+1)\) before multiplying to calculate quickly.
Frequently asked questions
What is the correct answer to this question?
630
Why is this the correct answer?
The sum of the first \(n\) natural numbers is \(S_n=\frac{n(n+1)}{2}\). Therefore, \(S_{35}=\frac{35\times36}{2}=35\times18=630\). Hence, 630 is correct. Values such as 620 and 640 do not result from this formula. Exam tip: Cancel 2 with the even factor in \(n(n+1)\) before multiplying 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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