Open Middle®
Directions: Using the digits 1 to 9, at most one time each, place a digit in each box to find the the greatest possible value for x.
Hint
Where should the 9 go or not go? Where should the 1 go or not go?
Answer
(1/8)x + 2 = 9 yields a solution of 56.
(1/9)x – 8 = 7 and (1/9)x – 7 = 8 both have a solution of 135.
Source: Chase Orton and Mark Goldstein
A student asked me about the value of x and since it’s on the page twice it implies they are the same value. Great activity!!
Amber, How did you create those slides? Thanks so much for sharing!
Thanks for sharing! This is awesome!
Thank you for sharing this!!
Is there an answer key?
Hi there. I have a question for this activity. You said that we could not repeat the same digits, but you repeated the 1 in your answer key. Is that a mistake or can we make our answers like that?
Think of it as two separate problems.