James A. H. Hunter, "Mathematical Brain-Teasers"
1976 | ISBN-10: 0486233472 | 111 pages | Djvu | 1 MB
1976 | ISBN-10: 0486233472 | 111 pages | Djvu | 1 MB
150 tantalizing teasers including coin and change problems, relative ages, time and distance, and 40 alphametics—innovative letter substitutions. Solutions.