"Singapura Mathemetica" has 212 pages. The day I bought it I read exactly half. The next day I read one-third of what was left. On the day after that I read one-quarter of what remained. What fraction of the Singapore math playbook remained unread?
212 pages at start
after one day, 106 pages left
next day, read (1/3)(106) or 35 1/3 pages
leaving 70 2/3 pages to read
last day , read (1/4)(70 2/3) or 17 2/3 page, leaving
70 2/3 - 17 2/3 or 53 pages to read
Did you intend to have fractional pages unread or read ?