The book contains 55 problems, of 4 different types.
The first type is addition problems, where the numbers have been replaced by letters and you have to work out what the letters are worth. All the problems can be solved logically, without having to resort to guesswork, but this type of problem is best when the words chosen are connected in some way, which is not the case here. Mom + mop = yoyo is just lazy puzzle setting.
The second type is the same idea, with multiplication problems. An issue here is that the questions require understanding of long multiplication, which is not the method taught at a lot of schools these days.
The third type is logic problems. You are given the answers of a group of students to a quiz, plus some clues, and you have to work out what the correct answers were. Again, the problems are well designed, requiring you to use slightly different methods each time to solve them, but none of them are especially interesting.
The fourth type is true / false worded logic problems which are frankly a bit dull.
Overall, there are a handful of good puzzles, but the rest are too samey, too old fashioned or too uninteresting.