The heavy lines indicate areas (called cages) that contain groups of numbers that can be
combined (in any order) to produce the result shown in the cage, with the indicated math
operation. For example, 36× means you can multiply the values together to produce 36. Number in cages may repeat if not on the same row or column.
Click on the numbers in the top right part of the screen to select the number. Click on an empty box to write the number. Click on a previous written number to delete it.