Question

Calculate the sum of first n natural numbers given by your teacher through the
following activity. For example to find the sum of first four natural numbers,
take a square-grid piece of paper of 4 x 5 squares. Then cut it as shown in the
n(n+1)
figure. Hence verify the formula S = ""(Here n = 4)
- 4 (4+1) - 4x5
20
- n(n+1)
2
: S =
2
= 10
-
2.3
4 5
6
[Note: Here a = 1 and d = 1. The activity can be
done taking different values of a and d. Similarly,
you can find the sum of even or odd numbers, cubes of
natural numbers etc.)
8
9
10​

Answer 1

Answer:

You have answered your own question