Sum Skyscrapers [SSKY-5-005P]
Similar Puzzle Books
1000 Math Logic Puzzles – Collection I
US, CA; UK, IE, DE, FR, BE, ES, IT, NL, PL, SE; JP, AU 
Puzzles in this book: Kakuro, From 1 to X, Doppelblock, Futoshiki, Sign In, Digital Battleships, Index Sums, Tenner Grid, Number Cross, and Grades.
