Open Middle®
Directions: Using the digits 1 to 9 at most one time each, fill in the boxes to make the smallest (or largest) product.
Hint
What does the number on the left represent? What does the number on the right represent?
Answer
96 · 87 is one answer for the largest product. 13 · 24 is the smallest positive product and -96 + 87 is one answer for the smallest negative product.
Note: This problem’s difficulty can be adjusted by altering the number of digits (boxes), picking smallest or largest, or by picking either a positive, negative, or both.
Source: Robert Kaplinsky
