Visualizing One Million vs. One Billion

From the YouTube description: “There are lots of ways to compare a million to a billion, but most of them use volume. And I think that’s a mistake, because volume just isn’t something the human brain is great at. So instead, here’s the difference between a million and a billion, in a more one-dimensional way: distance.

The video is more than an hour long, which is the point. In the last minute of the video, he mentions what a trillion would be in the same scenario.

How to 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/

Another Poorly Written Word Problem: Index

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.

 

211

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.

No automatic alt text available.

Source: https://www.facebook.com/PointlessMathFact/photos/a.959625970716963.1073741828.958620490817511/1427111183968437/?type=3&theater

24601

Source: https://www.facebook.com/MathWithBadDrawings/photos/a.822582787758549/1999420776741405/?type=3&theater

Codes and Ciphers Teaching Resources Website

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

Incredibly difficult math puzzle

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).

 

 

Dividing fractions

No automatic alt text available.

Source: https://www.facebook.com/MathWithBadDrawings/photos/a.822582787758549.1073741828.663847933632036/1767946789888806/?type=3&theater

Repunit prime

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

R_n = \frac{10^n-1}{9} = 1111\dots1,

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

R_1 = 1

R_2 = 11

R_3 = 111

R_4 = 1,111,

and so on.

It turns out that R_{1031} is the largest known prime repunit number.

Source: http://mathworld.wolfram.com/Repunit.html

Pizza Hut Pi Day Challenge: Index

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.