Sums III: Curious Pattern

5 followed by (n-1) zeroes and again 5 followed by (n-1) zeroes. n=number of zeroes given in the question. (OR) n(n+1)/2 = 1000000000*1000000001/2 = 500000000500000000

5+5 gives 10, we write 55.

50+50 gives 100, we write 5050.

500+500 gives 1000...

Considering that pattern, 500000000+500000000 gives 1000000000

We write 500000000500000000.

It is 5 then 8 zeroes again 5 then again 8 zeroes. So, is the pattern which gives us the answer $\color{#69047E}{\boxed{500000000500000000}}$ .

calculate how many numbers 0, if 10, no 0. then if 1000.000.000 right number of zeros there are 9 numbers. then n-1, that's the result. description of the quantity n 0. then this is the result, 9-1 = 8. then 10 ^ 9 = 500000000500000000

Hey yo,

as a = 1 , d=1 ,

S(10^9) = 10^9 / 2 x [ 2(1) + (10^9 -1) ]

S(10^9) = 5.000000005 x 10^17

Thanks...

this one is more logical than AP . i think question should be solved without using calci. 1 to 10 = 55 1 to 100 = 5050 , 2 zero in 100 . so put 2-1 zero after both 5's. 1 to 1000 = 500500 , samething 1 to 1000000000 = 500000000500000000, 9 zero put 8 after both 5's