The basic idea of TenBlocks is: choose a multiplication problem in the right-hand grid, and then fill in blocks of ten in the left hand grid. There are two types of blocks you can fill in: 2 times 5, which you do by dragging out a rectangle in the required position with the mouse, and 3 times 3 with an extra 1, which you do by dragging out a 3 times 4 rectangle. To delete a rectangle that you have placed, click on it to select it, and then press delete, backspace or press the "Remove Block" button. When you have filled in as many blocks of ten as possible, i.e. there are less than ten squares not filled in, you have finished that problem (as shown by a change of colour), and you can select the next one to do. Keep going until you have done them all.