Answer
Monday: 2/9
Tuesday: 1/6
Wednesday : 2 x 1/6 = 2/6 = 1/3
Total pages read :
2/9 + 1/6 + 1/3 =
(2 x 2) + (1 x 3) + (1 x 6) / 18 =
(4 + 3 + 6) / 18 =
13/18
The total book's pages is : 18/18
Thomas read 13/18
so the rest of unread pages :
18/18 - 13/18 =
(18 -13)/18 =
5/18