Another play with numbers website

  • Thread starter suyver
  • Start date
  • Tags
    Numbers
In summary, the "Another play with numbers" website offers a unique and interactive platform for users to engage with various mathematical concepts and games. The website provides a range of activities and challenges that allow individuals to improve their numerical skills while having fun. It also offers educational resources and tutorials for users to learn and develop their understanding of math. With its user-friendly interface and diverse content, the "Another play with numbers" website is a valuable resource for both students and math enthusiasts alike.
  • #1
suyver
248
0
Another "play with numbers" website

http://digicc.com/fido/

It's probably related to the fact that we have a base-10 number system, but I fail to see how it works...

This website does the following:
1) You write down a 3 or 4 digit number, say X=x1 x2 x3 x4 (where the x's denote the digits).
2) You randomize the digits and obtain another number, say Y=x3 x2 x4 x1.
3) You subtract the largest from the smallest one. (call this one Z=z1 z2 z3 z4)
4) You select one of the digits from this number (say z3) and write the remaining numbers in any order, say z4 z1 z2 in my example.
5) Somehow, the website then tells you what the selected digit was (the z3 in my case) based only on this remaining number.

Can someone explain in some more detail what the trick is?
 
Last edited:
Mathematics news on Phys.org
  • #2
OK, I got slightly further: My number Z=X-Y (X>Y) must be devidable by 9, right?

Is it then just the case that because the website knows that the number I imput plus the unknown digit must be dividable by 9, the value of the unknown digit can be determined? I.E.: Because it knows that the number (z4 z1 z3 UNKNOWN) is devidable by 9, and because it knows z4, z1 and z3, it can determine the value for the UNKNOWN, since z4+z1+z3+UNKNOWN must be devidable by 9?
 
  • #3
OK, I think I completed the answer to my own question (great forum, this is! ;-)

This trick is that the website divides the number that I imput by 9 to see what remainder is left.
If it's 0, the missing digit had to be 9.
If it's 1, the missing digit had to be 8.
If it's 2, the missing digit had to be 7.
If it's 3, the missing digit had to be 6.
If it's 4, the missing digit had to be 5.
If it's 5, the missing digit had to be 4.
If it's 6, the missing digit had to be 3.
If it's 7, the missing digit had to be 2.
If it's 8, the missing digit had to be 1.

Is this correct?
 
  • #4
There is perhaps the issu to be got round of: if the remainder is 0, then the missing digit might be 0 (it is congruent to zero mod 9 and there are two possbilities) of course there should be some reason why one of these can't happen, or there might be other reasons that allow you to decide which of these possibilites is true if both can occur
 
  • #5
Good point! That must be why you are not allowed to choose a zero in the link that I gave.
 

What is "Another play with numbers" website?

"Another play with numbers" website is a platform that provides interactive games and activities related to mathematics and numbers. It offers a fun and engaging way for individuals of all ages to improve their mathematical skills and knowledge.

What types of games and activities are available on "Another play with numbers" website?

There are various types of games and activities available on "Another play with numbers" website, including number puzzles, math quizzes, logic games, and more. These games are designed to challenge and enhance your mathematical thinking and problem-solving abilities.

Is "Another play with numbers" website suitable for all ages?

Yes, "Another play with numbers" website is suitable for individuals of all ages. The games and activities are designed to cater to different levels of difficulty, making it suitable for children, students, and even adults.

Can I track my progress on "Another play with numbers" website?

Yes, you can track your progress on "Another play with numbers" website. The platform offers a feature that allows you to save your scores and monitor your improvement over time. This can help you identify areas where you need improvement and set goals for yourself.

Is "Another play with numbers" website free to use?

Yes, "Another play with numbers" website is free to use. You can access all the games and activities without any cost. However, some features and advanced levels may require a paid subscription.

Similar threads

  • General Math
Replies
4
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
14
Views
2K
Replies
1
Views
4K
Replies
4
Views
384
Replies
1
Views
885
  • General Math
Replies
2
Views
1K
Replies
57
Views
4K
  • Computing and Technology
Replies
4
Views
742
  • Calculus and Beyond Homework Help
Replies
11
Views
1K
  • Set Theory, Logic, Probability, Statistics
Replies
14
Views
917
Back
Top