# 42nd Carnival of Mathematics

It’s the 42nd Carnival of Mathematics. Don’t panic!

First, the customary trivia about the number of the Carnival.

• 42, Jackie Robinson’s jersey number, is the only number retired by all Major League Baseball teams.
• 42 is a domino game, especially popular in Texas.
• 42 is the top result for the Google search “answer to life, the universe, and everything.”

And now on to the posts.

TwoPi at the 360 blog presents two fun articles using advanced techniques to prove elementary results, Using calculus to derive the quadratic equation and Integration by parts via iterated integrals.

Next, Barry Leiba discusses the use of logic in mathematics in Modus ponens, modus tollens, and proof by contradiction posted at Staring At Empty Pages. The footnotes at the end have some interesting information on prime numbers, factorization, and cryptography.

Moving from philosophical logic to hardware logic, Himadri Choudhury illustrates how a seemingly trivial problem becomes interesting when you look into it deeply enough. He presents a clever algorithm for simultaneously adding three integers more efficiently in a microchip. Check out Multiple Operand Adder posted at Thread Pool for an insight into the work that goes into operations most of us take for granted.

Moving higher up the computing levels of abstraction, Samuel Jack combines mathematics and computer science in presenting his solutions to problems 18 and 67 from Project Euler. See Project Euler Problems 18 and 67: Finding the Maximal Route through a Triangle posted at Functional Fun. He also presents his solution to problem 15 in the same series in City Grids and Pascal’s Triangle.

Finally, MBB explains how the check-sum algorithm works on major credit cards in Generation Of Luhn Algorithm Credit Card Numbers posted at Money Blue Book Finance Blog. This algorithm will detect any error that changes a single digit and will detect most errors that transpose consecutive digits.

Jason Dyer will host the 43rd Carnival of Mathematics at The Number Warrior on November 7. Submit your articles for the next Carnival here.

## 3 thoughts on “42nd Carnival of Mathematics”

1. I’m hosting #43 at The Number Warrior.

2. Thanks, Jason. I edited the post to include your blog as the next location.

3. Abhishek

the illustration given is wrong. The maximum sum should be 5+15+29+85 = 105

The example provided by the author: 5+15+29+45 = 94 seems to be incorrect.

Correct me if I am wrong…