Remainder Graphs

​
modulus
7
What is the remainder when some number
n
is divided by another number, for example, 7? The result is called
n(mod7)
. You can find the answer quickly with the help of one of the graphs in this Demonstration.
For a number, say
n=9406
, select the desired modulus, then start at 0 and follow 9 blue arrows, 1 red arrow, 4 blue arrows, 1 red arrow, 0 blue arrows, 1 red arrow, then 6 blue arrows. If there is no red arrow, stay in place. Each digit specifies the number of blue arrows, then follow a single red arrow before moving on to the next digit. The number on your final landing place gives the remainder. In this example,
9406=5(mod7)
.

References

[1] D. Wilson, "Divisibility by 7 Is a Walk on a Graph," Tanya Khovanova's Math Blog (blog, T. Khovanova, owner), (Aug 11, 2009) blog.tanyakhovanova.com/2009/08/divisibility-by-7-is-a-walk-on-a-graph-by-david-wilson.

External Links

Chinese Remainder Theorem
Fractional Graphs and Flowers
Modular Arithmetic Tables
Remainder (Wolfram MathWorld)

Permanent Citation

Ed Pegg Jr
​
​"Remainder Graphs"​
​http://demonstrations.wolfram.com/RemainderGraphs/​
​Wolfram Demonstrations Project​
​Published: November 16, 2015