Question

find the sum of first 20 natural numbers? How much more the sum of first 40 natural numbers than this?

please answer this question
step by step​

Answer 1

Answer:

sum of first 20 natural numbers is 20(20+1)/2=210

sum of first 40 natural numbers is 40(40+1)/2=820

sum of first 40 natural numbers exceeds the sum of first 20 natural numbers by 610

Answer 2

Answer:

sum of first n natural numbers formula is n(n+1)/2

then sum of first 20 natural numbers is

20(20+1)/2 = 10*21 = 210

similarly the sum of first 40 natural numbers is

40(40+1)/2 = 20*41 = 820

so, it is 610 more than the sum of first 20 natural numbers