Open Middle®
Directions: Using the digits 1 to 9 at most one time each, place a digit in each box to find the second greatest solution.
Hint
You can use a number line to help. What do you need to think about to create the highest sum? What will you change to create the second highest?
Answer
863 (864 is the largest)
-123+986=863
-124+987=863
-123+986=863
-124+987=863
Source: Neil Hamilton
