Question

Shakuntla Devi, Karl Gauss, Archimedes could do a lot of quick maths since their young ages. Can you do better and find the sum of all the digits in integers from one and a billion. Note, that's all the digits in all the numbers, not all the numbers themselves.

Answer 1

Answer:

2.... 1+1,

As,

1,000,000,001

1+0+0+0+0+0+0+0+0+1=2