Decode these simple problems, work out the answer and find the matching self-correcting puzzle piece. Boys especially love the fact they are reading to solve maths problems and put extra effort in to read the words in these simple problems successfully. Tricky maths vocabulary that might not have been encountered is listed on the back of the box. Both sets cover number problems that require use of the four operations. The red phase set focuses on answers within 20, while the green phase progresses to problems that have answers within 100. There are 20 puzzles in each set and exciting activity instructions included on the box.