Multiplication tables have some wonderful and quite surprising patterns. This is one of them. Draw any rectangle in a multiplication…

Read morePennies to Heaven is a Fermi Problem, basically a “headmath” experiment. Fermi Problems, originally developed by Enrico Fermi, one of…

Read moreFractals are a new 21st century mathematics. They are patterns that repeat themselves at various scales. This one is based…

Read moreWe take that great old problem of the inventor of chess and the ruler of India and use it to…

Read moreScatterplot graphs enable us to build shapes using spreadsheets and to practice transformational geometry. They are surprisingly flexible tools. And…

Read moreStrings need not begin and end on axes that are at right angles to each other which we call Cartesian.…

Read moreSpreadsheets can be a great place for you to build your own games. Ryan has built one of his early…

Read moreHow many of the numbers from 1 to 100 are in the times table? All, Most, Less than half? I…

Read moreLet's do a little target practice with this spreadsheet projectile simulator, which will map out the flight path of an…

Read moreHave you ever played Sudoku? It is fun and challenging. You have to find the numbers from 1 to 9…

Read moreThough spreadsheets lets you put geometric shapes on the screen, those shapes are not connected with the cells and cannot…

Read moreThe usual way to make string diagrams using rubber bands or yarn on a board with nails does not allow…

Read moreWhat if you made a series of unit fractions with the odd numbers as their denominator, added the first two…

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