Switch between day and night to get MathPup to the bone on each level. At the start of each level you'll need to answer the multiplication problem correctly before you can switch.
Click the Instructions button on the main menu to see the detailed instructions. Note that you will have to click the down arrow key or button to switch between day and night and that you'll need to do that at the start of each level to bring up the multiplication problem. Note that some dangers are not visible. Be on the lookout for signposts indicating those types of dangers.