Photo by Brian – Progressive Spin.
Logic is the science of making valid deductions and proofs — and it is also a fruitful topic for blackboard quotes. Here are a few of my favorites:
You can only find truth with logic if you have already found truth without it.
Remember the Math Adventurer’s Rule: Figure it out for yourself! Whenever I give a problem in an Alexandria Jones story, I will try to post the answer soon afterward. But don’t peek! If I tell you the answer, you miss out on the fun of solving the puzzle. So if you haven’t worked these problems yet, go back to the original posts. Figure them out for yourself — and then check the answers just to prove that you got them right.
While checking out the book table after a homeschool group meeting, Maria Jones glanced up to see her children laughing with some kids she did not recognize. Driving home, she asked about the new family, but Alex and Leon had been too busy exchanging silly stories to even ask the strangers’ names.
“Well,” Leon said, “the boy told me he has twice as many sisters as brothers.”
No way!” said Alex. “The girl told me that she has the same number of brothers and sisters.”
How can that be?
Leonhard Jones is Alexandria Jones’s younger brother. He enjoys woodworking, and he cut a wooden cube into 8 smaller blocks to make himself a puzzle.
Leon painted the 8 blocks with his two favorite colors: red and forest green. When he was finished, Leon could put the blocks together into a red cube, or he could switch them around to make a green cube.
How did Leon paint his blocks?
Photo by Windell Oskay via Flickr (CC BY 2.0).
Math concepts: logic, patterns, divisibility
Number of players: 2
Equipment: 10 tokens, any sort, mix or match
Place the pile of tokens (pebbles, toothpicks, beans, pennies, dry cereal, etc.) on the table between the players.
Can you solve the Wason Selection Task puzzle at Text Savvy blog? [Blog has disappeared.]
Here is an interactive version of the Wason Selection Task, and you can find out more information about it on the Wikipedia page.
Warning: Don’t read the comments Wikipedia page until you have tried the puzzle for yourself. Why ruin your fun?
If you enjoy Raymond Smullyan’s The Lady or the Tiger and similar puzzles, you will probably have fun with this Logic test, posted by JD2718. JD has a wide variety of other math puzzles at his site, so take the time to browse a bit.
It’s been ages since I shared the blackboard quotes from my co-op math classes. Here are some of our recent ones for your reading pleasure…
I want to tell you a story. Everyone likes a story, right? But at the heart of my story lies a confession that I am afraid will shock many readers. People assume that because I teach math, blog about math, give advice about math on internet forums, and present workshops about teaching math — because I do all this, I must be good at math.
Apply logic to that statement. The conclusion simply isn’t valid. …
Update: This post has moved.
[Rescued from my old blog.]
I have been reading up on Charlotte Mason’s teaching style, and I plan to incorporate more copywork and dictation into our school program next year. Here are a few of my favorite funny quotes about math. (These would also make great blackboard quotes for a math classroom.)
Denise Gaskins' Let's Play Math 