What Is The Other Missing Number?

Logic Level 3

$\LARGE{\begin{aligned} \boxed{\phantom0} \; + \; \boxed{\phantom0} \; - \; \boxed{\phantom0} \; &=& \; \boxed{\phantom0} \\ \boxed{\phantom0} \; \times \; \boxed{\phantom0}\; \div \; \boxed{\phantom0} \; &=& \; \boxed{\phantom0} \\ \end{aligned}}$

Put one of the integers $1, 2, \ldots , 9$ into each of the boxes, such that eight of these numbers are used once (and one number is not used at all) and both equations are true.

What is the sum of all possible values of the missing number?

Inspiration .

The answer is 23.

1 solution

A Former Brilliant Member
Jul 15, 2016

The only two possible scenarios are: 1. (9 x 2) / 3=6 , 8+4-7=5 which 1 is left out and 2. (8 x1) / 2 = 4, 9+3-5=7 which 6 is left out.

Another Scenario is (2 x 3)/6 = 1 ; 4 + 9 - 8 = 5, so we're also left with 7

Joshua Burton - 4 years, 11 months ago

And another way is to inverse position of 6 and 1 in your solution Joshua... I think this problem might be wrong...

Romain Milon - 4 years, 11 months ago

Other solution... $1 \times 6 / 3 = 2$ and $7 + 5 - 8 = 4$ . Where is the 9?...

Guillermo Templado - 4 years, 11 months ago

1*6:2=3 4+8-5=7 9 is left out

Hasmik Garyaka - 2 years, 4 months ago

What Is The Other Missing Number?

The answer is 23.

1 solution

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