Question

Find the Sum of all natural numbers from 21 to 80 { ans 30, 30)

Arithmetic equation ​

Answer 1

Answer:

3030

Step-by-step explanation:

by a.p. series

we know the formula of sum of the a.p. series=

n/2{2a+(n-1)d}

where, a= first digit in the series

d=difference between the first two digits

n= th term

i.e,. 60/2{2×21+(60-1)1}= 30{42+59}=30×101=3030