##
   ##
  ###
+ ###
 ####

In the above addition all the digits were replaced by "#".
Please restore the original numbers, given that in each column the digits form a valid arithmetic progression.

• Based upon a puzzle by Polish mathematician Marek Penshko.

After finally realizing that arithmetic progressions can go 'backwards', a lot of trial and error yielded the following addends:

28

36

844

752

Posted by Bryan on 2014-05-19 13:01:37