Question

find the sum of all three digit numbers which are divisible by 12

Answer 1

lowest 3 digit no. is 100 and highest 3 digit no. is 999
to find how many divisible by 12
first divide 100 by 12 u get remainder not equal to 0 the first no. is 108 and last no. is 996

so just use A.P SUMMISION FORMULA
as below

= n[2a +(n-1)d]/2

Answer 2

Answer:

108,120,132,......996.

l= a+(n-1) d

996=108 +(n-1) *12

n-1=888/12=74

n=75

Sn= n/2 *(a+l) = 75/2 *(108+996) =75*552=41400 ✅✅✅