This is the link to a kumon answer site. The site got shut down but once u hit this link another link pops up and it takes u to a page with answers.
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwiM3MKs5_nxAhUUGFkFHVckDKsQFjABegQIBBAD&url=https%3A%2F%2Fsites.google.com%2Fview%2Fkumonanswers%2Fhome%3Fauthuser%3D0&usg=AOvVaw0FOYelzEOEXFnzckpsRUEe