Question

the sum of the first 20 natural no is ?​

Answer 1

Hi mate ,

First you need to understand a short trick , or maybe a formula to solve these type of questions .

so, the formula for finding the sum of the first 'n' natural numbers (where n is the no. of numbers) is :

[n*(n+1)]/2

so now you have acquainted this fact , moving on to the question .

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A/Q,

the number of numbersfrom 1 to 20 is = 20     [ as its asking for natural no. so we have started with 1 as it is the first natural number]

so putting the value of n which is 20 here in the equation , we get,

[20*(20+1)]/2                     [ using bodmass rule ]

=[20 *21]/2

=420/2

=210

hence , we get the sum of first 20 natural numbers as 210 .