
Math concepts: multiplication, mental calculation, times table
Number of players: one leader (teacher) and two or more players
Equipment: free MINGO number cards and boards; bingo chips, pennies, or other tokens to cover numbers

Math concepts: multiplication, mental calculation, times table
Number of players: one leader (teacher) and two or more players
Equipment: free MINGO number cards and boards; bingo chips, pennies, or other tokens to cover numbers
Categories: Games · Middle elementary
Tagged: Arithmetic, Elementary school, Games, Math facts, Multiplication
I heard of this contest in an e-mail from ClickSchooling:
Kids, share your creative math ideas! Describe how you use math in any activity you love to do — a sport, game, craft, hobby, or anything else.
Send in a description of the activity and it uses math, as well as any drawing(s) or diagram(s). There are many great prizes to be won. Please ensure you’ve read and understand our contest’s rules and regulations before entering.
Sounds like fun! If you want to enter, act quickly. Entries must be submitted online by July 30th. Visit Crazy4Math.com for more information and to check out the winners from previous years.
Categories: Activities · Grades 5+up · Middle elementary
Tagged: Activities, Elementary school, High school, Math contests, Middle school, Writing
Picture from MacTutor Archives.
After the Pythagorean crisis with the square root of two, Greek mathematicians tried to avoid working with numbers. Instead, the Greeks used geometry to demonstrate mathematical concepts. A line can be drawn any length, so straight lines became a sort of non-algebraic variable.
You can see an example of this in The Pythagorean Proof, where Alexandria Jones represented the sides of her triangle by the letters a and b. These sides may be any length. The sizes of the squares will change with the triangle sides, but the relationship is always true for every right triangle.
Categories: Alexandria Jones · Algebra & beyond · History
Tagged: Alexandria Jones, Algebra, Area, Distributive property, Euclid, Geometry, History, Multiplication, Proofs, Puzzles
[Photo by SuperFantastic.]
Keith Devlin’s latest article, It Ain’t No Repeated Addition, brought me up short. I have used the “multiplication is repeated addition” formula many times in the past — for instance, in explaining order of operations. But according to Devlin:
Multiplication simply is not repeated addition, and telling young pupils it is inevitably leads to problems when they subsequently learn that it is not.
I found myself arguing with the article as I read it. (Does anybody else do that?) If multiplication is not repeated addition, then what in the world is it?
Categories: How & Why · Middle elementary · Uncategorized
Tagged: Addition, Arithmetic, Keith Devlin, Middle elementary, Mistakes, Multiplication, PUFM, Teaching
[Photo by Vox Efx.]
School’s out — and what could be more fun in the lazy, hazy days of summer than to study math? Check out these articles from Maria Miller of Homeschool Math Blog:
Categories: Grades 5+up · Middle elementary
Tagged: Arithmetic, Elementary school, Homeschool Math Blog, Homework, Middle school, Resources, Word problems

Photo by jaycoxfilm.
Math concepts: mental calculations, math vocabulary, and anything else you want to include
Number of players: any number, but I think it works best with two players who alternate asking questions
Equipment: imagination and, if necessary, scratch paper
Many years ago, I read a magazine article by mathematical music critic Edward Rothstein, wherein he described a game he invented for his daughter:
“What number am I? If you add me to myself, you get four.”
Rather than explaining the rules of the game, let me tell you a story…
Categories: Family · Games · Grades 5+up · Middle elementary · PK-1st grade
Tagged: Arithmetic, Elementary school, Games, Mental math, Middle school, My family, Word problems
[In the last episode, Alexandria Jones received a letter from archaeologist Sofia Theano, asking for help with a Pythagorean puzzle.]
Categories: Alexandria Jones · Algebra & beyond
Tagged: Alexandria Jones, Geometry, Pythagorean Theorem
We continue to excavate the ancient building complex, which I believe may have been Pythagoras’s school. Yesterday, one of our digging crews uncovered a mosaic tile floor in the courtyard. The pattern of the tiles alternates between two square designs. (See enclosed sketches.)
During your family’s recent visit, you expressed an interest in the mathematical ideas of Pythagoras. Could you or your father offer us any insight into what these tile designs may represent?
I look forward to your response.
Sincerely,
Sofia Theano, Ph.D.
Crotone, Italy
Categories: Alexandria Jones · Algebra & beyond
Tagged: Alexandria Jones, Geometry, Pythagoras, Pythagorean Theorem

Photo by paparutzi.
Math concepts: addition, subtraction, negative numbers, mental math, absolute value
Number of players: any number
Equipment: math cards (two decks may be needed for a large group)
Categories: Games · Grades 5+up · Middle elementary
Tagged: Subtraction, Arithmetic, Math club, Games, Addition, Negative numbers, Math cards
[When Alexandria Jones and her family visited an excavation in southern Italy, they learned several tidbits about the ancient school of mathematics and philosophy founded by Pythagoras. Here is Alex's favorite story.]
It hit the Pythagorean Brotherhood like an earthquake, a crisis of faith which shook the foundations of their universe. Some say Pythagoras himself made the dread discovery, others blame Hippasus of Metapontum.
Something certainly did happen with Hippasus. The Brotherhood sent him into exile for insubordination, or for breaking the rule of secrecy — or was it for proving the unthinkable? According to legend, Hippasus drowned at sea, but was it a mere shipwreck or the wrath of the gods? Some say the irate Pythagoreans threw him overboard…
Categories: Alexandria Jones · Algebra & beyond · History
Tagged: Algebra, Hippasus, History, Irrational numbers, Natural numbers, Pythagoras, Ratios

Photo by jetheriot.
One of the most common math questions on homeschooling discussion forums is, “How can I help my child master the math facts?” Unfortunately, when it comes to drilling facts, many children think math is spelled “B-O-R-I-N-G.” Worksheets are tedious, flash cards make them groan, and even the latest computer game is a yawner.
Categories: Middle elementary
Tagged: Arithmetic, Math facts, Elementary school
Math concepts: odd numbers, even numbers, greater-than/less-than, rounding off, addition, subtraction, multiplication, division, fractions, negative numbers, prime numbers, square numbers, problem solving, mental math
Number of players: two or more
Equipment: pencil (or pen) and paper for every player
Categories: Games · Grades 5+up
Tagged: Activities, Arithmetic, Games, Math club, Mental math, Pre-algebra, Problem solving