Question

1+2+3.........+n is equal to
​

Answer 1

Answer:

$\large\boxed{\sf{\dfrac{n(n+1)}{2}}}$

Step-by-step explanation:

We have to find the sum of,

1 + 2 + 3 +.............+ n

Clearly, it's the sum of first n terms of natural number.

And, the sum of first n natural numbers is given by the formula $\bold{\dfrac{n(n+1)}{2}}$

Answer 2

Answer:

1०+2०+3०+ is equal to

a 0

b 1

c -1

d non of these