What is the sum of all the digits in all the integers from one to one million?
Don’t do a lot of tedious adding up – think mathematically!
Note: the digits in the integers from one to ten add up to 46
(not 55 because 10 contributes only 1 to this sum.)
Now introduce zero.
Every number except one million has a special partner.
This problem is adapted from the NRICH task Digit Sum with permission of the University of Cambridge. All rights reserved.