A Math Riddle Resurfaces

Many people are relieved to leave math behind after school, yet online puzzles have sparked renewed interest.

As the article puts it, “the process of working my way through internet riddles and puzzles is something I’m now quite taken with.”

The Challenge\

Readers were invited to test their logic with a viral problem:
“1+4=5, 2+5=12, 3+6=21, 5+8=?”
The question quickly divided the internet.

Why It’s Tricky

The puzzle has no single method. The article stresses that “there’s more than one correct answer,” depending on how patterns are interpreted.

Multiple Answers

Five different solutions are presented, producing answers such as 45, 34, 32, 111, and 1101.

The takeaway isn’t speed or precision, but creativity—and enjoying the mental workout.

Solution Five

1 + 4 = 5
2 + 5 = 7 (base 5) =12
3 + 6 = 9 (base 4) = 21
4 + 7 = 11 (base 3) = 102
5 + 8 = 13 (base 2) (aka binary) = 1101
ALGORITHM: for {X=6, C = (A + B)^(10 -> X), X -1} (First answer in Base6, then
Base 5, then 4, etc…including “missing” numbers
ANSWER = 1101