What is the sum of the opposite sides of the common dice?

Have you known that the sum of every two opposite sides of common dice is equal to 7? As you know, common dice are small cubes 1-2 cm along an edge with faces being numbered from one to six.

It has been traditional to assign pairs of numbers which sum equals seven to opposite faces since at least classical antiquity.

More Info: cs.mcgill.ca

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72 Comments

Jaimi McEntire

die. Dice is plural. Plus they can have different numbers of sides. Question should be: "What are the sum of the pips on opposite sides of a six-sided die".

John Bach-Hansen

I didn't understand the Q.

Jim Mascair

I used the picture to help me figure it out. There were just enough dies to figure out the remainder.

Kat

It was an odd question, but I got there in the end!

Mary Hale

Thank you.

earlepg

Took a few seconds to figure out what was asked and then to work it out, but I eventually got it.

dsneed

tesla alset, I got that right away. So many are making this so difficult. You are my equal.💕 Dianne

dsneed

Well, the picture showed five and six. Logically that would lead to ace and two. Mr. Scarecrow has a brain. Yay me.

Chris Braun

Had no idea, but 7 is the only one it could be. It could never be more than the lowest number plus the highest number no matter how many sides because the lowest number (1) can't go with a number higher than the highest number. And it would have to have an even number of sides for each side to have an opposite side. It has to be the total number of sides + one (n+1) no matter how many sides if the sides start at 1 and go in numerical order...if that made sense lol it makes logical sense to me but hard to explain. Basically it's gotta have an even number of sides and the answer is always n+1, I think I'm confusing myself now😂