Fill in the numbers 1-9 in the nine blank squares. The goal is to get the numbers to add up to 15 in horizontal, vertical and diagonal directions. Each number could only be used once.
On the Kindle Keyboard use the 4-way controller to move to the square you want and push the centre key to select. Then use the top row of keys (qwertyuiop) with the <Alt> key to type the number.