News You Can Use, courtesy of Popular Mechanics: The mathematical ways to most efficiently mow your yard, by shape of yard.

https://www.popularmechanics.com/science/math/a28722621/mow-your-lawn-using-math/

News You Can Use, courtesy of Popular Mechanics: The mathematical ways to most efficiently mow your yard, by shape of yard.

https://www.popularmechanics.com/science/math/a28722621/mow-your-lawn-using-math/

*Posted by John Quintanilla on May 15, 2020*

https://meangreenmath.com/2020/05/15/how-to-mow-your-lawn-using-math/

I’m doing something that I should have done a long time ago: collecting a series of posts into one single post. The following links comprised my series poorly written word problem, taken directly from textbooks and other materials from textbook publishers.

Part 1: Addition and estimation.

Part 2: Estimation and rounding.

Part 3: Probability.

Part 4: Subtraction and estimation.

Part 5: Algebra and inequality.

Part 6: Domain and range of a function.

Part 7: Algebra and inequality.

Part 8: Algebra and inequality.

Part 9: Geometric series.

Part 10: Currently infeasible track and field problem.

Part 11: Another currently infeasible track and field problem.

*Posted by John Quintanilla on October 21, 2019*

https://meangreenmath.com/2019/10/21/another-poorly-written-word-problem-index-3/

Set a digital clock to display in 24-hour (military) time. Each day, it will show you 211 prime numbers starting with 00:02 (2 minutes after midnight) and ending with 23:57 (3 minutes before the next midnight.)

Oh, and 211 is also prime, so 02:11 would be one of the 211 prime times you observe each day.

*Posted by John Quintanilla on February 11, 2019*

https://meangreenmath.com/2019/02/11/211/

*Posted by John Quintanilla on January 25, 2019*

https://meangreenmath.com/2019/01/25/24601/

Somehow I found this fun website with various teaching resources using different coding and decoding methods: http://www.cimt.org.uk/resources/codes/?fbclid=IwAR2yX_yDK0UAmLB2acIgbk15wJMy_QXFJSuKaQOj3q-SlrFkuuuxpsEXoyI

*Posted by John Quintanilla on January 18, 2019*

https://meangreenmath.com/2019/01/18/codes-and-ciphers-teaching-resources-website/

For math/puzzle enthusiasts (as well for as my own future reference): This was one of the most diabolically difficult puzzles that I’ve ever seen. The object: use the numbers 1-9 exactly once in each row and column while ensuring that the given arithmetical operation in each cage is also correct. Here it is. Fair warning: while most MathDoku+ puzzles take me 20-40 minutes to solve, this one took me over 3 hours (spread out over 5 days).

*Posted by John Quintanilla on May 21, 2018*

https://meangreenmath.com/2018/05/21/incredibly-difficult-math-puzzle/

*Posted by John Quintanilla on January 5, 2018*

https://meangreenmath.com/2018/01/05/dividing-fractions/

In the United States, today is abbreviated 10/31. Define the th repunit number as

,

a base-10 number consisting of consecutive 1s. For example,

,

and so on.

It turns out that is the largest known prime repunit number.

*Posted by John Quintanilla on October 31, 2017*

https://meangreenmath.com/2017/10/31/repunit-prime/

I’m doing something that I should have done a long time ago: collecting a series of posts into one single post. The following links comprised my series on the 2016 Pizza Hut Pi Day Challenge.

Part 1: Statement of the problem.

Part 2: Using the divisibility rules for 1, 5, 9, 10 to reduce the number of possibilities from 3,628,800 to 40,320.

Part 3: Using the divisibility rule for 2 to reduce the number of possibilities to 576.

Part 4: Using the divisibility rule for 3 to reduce the number of possibilities to 192.

Part 5: Using the divisibility rule for 4 to reduce the number of possibilities to 96.

Part 6: Using the divisibility rule for 8 to reduce the number of possibilities to 24.

Part 7: Reusing the divisibility rule for 3 to reduce the number of possibilities to 10.

Part 8: Dividing by 7 to find the answer.

*Posted by John Quintanilla on August 22, 2017*

https://meangreenmath.com/2017/08/22/pizza-hut-pi-day-challenge-index/

Here’s a tale of one the great mathematicians of all time that I heard for the first time this year: the great mathematician published a mistake… which, when it occurs today, is highly professionally embarrassing to modern mathematicians. From *Mathematics in Ancient Greece*:

In a paper published in the year 1774, [Leonhard] Euler listed [1,000,009] as prime. In a subsequent paper Euler corrected his error and gave the prime factors of the integer, adding that one time he had been under the impression that the integer in question admitted of the unique partition

but that he had since discovered a second partition, namely

,

which revealed the composite character of the number.

See Wikipedia and/or Mathworld for the details of how this allowed Euler to factor .

*Posted by John Quintanilla on August 3, 2017*

https://meangreenmath.com/2017/08/03/euler-and-1000009/