In this calculation maze the aim is to start at the top left corner, and find the shortest route to the bottom right corner ending up with a total of 7.
At each step you obey the instruction in the box. For example, if you take four steps right from the starting position you get the successive totals -1, 0, -1, and +4. If you then take four steps down you get the successive totals +3, +4, +3, and +6. So unfortunately that route doesn’t reach the goal with the correct total of 7.