This is a 5×5 grid. The first row from left to right contains the numbers 1, 2, 3, 4, and 5; the second row contains 6, 7, 8, 9, and 10; the third row contains 11, 12, 13, 14, and 15; the fourth row contains 16, 17, 18, 19, and 20 and the final row contains 21, 22, 23, 24, and 25. The numbers 3, 6, 15, 17 and 24 have been shaded