Find the sum of 1-2-3-4-5-6 - -14 -15

Finding the sum:We know that, Sum of the first n natural number=n(n+1)/2We have given 1+2+3+4+5+6 ……… ..+14 +15Where, n=15 (Total number of terms)Sum of natural ...

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Standard X

Mathematics

Sum of First n Natural Numbers

Find the sum ...

Question

Find the sum of $1 + 2 + 3 + 4 + 5 + 6 \dots \dots \dots . . + 14 + 15$

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Solution

Finding the sum:
We know that, Sum of the first $n$ natural number $= \frac{n (n + 1)}{2}$
We have given $1 + 2 + 3 + 4 + 5 + 6 \dots \dots \dots . . + 14 + 15$
Where, $n = 15$ (Total number of terms)
Sum of natural number $= \frac{n (n + 1)}{2}$
$= \frac{15 (15 + 1)}{2}$
$= \frac{15 (16)}{2}$
Therefore, the sum of natural numbers from $1$ to $15$ is $120$ .

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Find the sum of 1+2+3+4+5+6………..+14+15

Finding the sum:We know that, Sum of the first n natural number=n(n+1)2We have given 1+2+3+4+5+6………..+14+15Where, n=15 (Total number of terms)Sum of natural number=n(n+1)2 =15(15+1)2 =15(16)2Therefore, the sum of natural numbers from 1 to 15 is 120.

Find the sum of $1 + 2 + 3 + 4 + 5 + 6 \dots \dots \dots . . + 14 + 15$