Directions: Using the digits 1 to 9 at most one time each, place a digit in each box to make a true pattern.
How can we tell whether the digits we place in the boxes actually make a pattern? How can we tell if the pattern increases each time by the digit we choose? How can we tell what would be a bad digit to choose for how much it increases by?
There are many possible answers including 8, 17, 26 increases by 9.
Source: Robert Kaplinsky
5 7 2 3 4 9
7 3 4 5 8 6