Subtraction Magic with 3 Digits

Subtraction Magic with 3 Digits

 Subtraction Magic with 3 Digits (Martin Gardner or earlier) Students need to reliably add and subtract numbers of several digits in order for this to work in the classroom. It is not a good trick to teach these, but rather to review something that 80% of students...
Animal Subtraction

Animal Subtraction

Animal Subtraction The Graceful Tree Conjecture (Ringel et al., 1967) These puzzles are the best way to introduce students to subtraction.  The puzzle is based on a classic unsolved problem that deserves to be in every student’s experience of mathematics. The...
Squaring the Square

Squaring the Square

Squaring the Square (R. L. Brooks, C. A. B. Smith, A. H. Stone and W. T. Tutte, 1930s) Give students addition and subtraction practice and link these numerical activities to geometry. A fraction of students, predominantly girls, thrive when the beauty of mathematics...
Place Value

Place Value

Place Value (MathPickle, 2011) Some number systems use place value – others do not. This video takes you on a tour of number systems including Egyptian, Arabic, Babylonian, Montessori and Scientific Notation. Ron Goodman has edited the video for younger students...
Venus Flytrap – dangerous decimals

Venus Flytrap – dangerous decimals

This is a game to give your students an intuition about fractions. Start by dividing your class into teams. Each team is randomly dealt six cards 1-100 (alternatively they can choose six numbers 1-100.) I'm going to colour the cards to indicate which team they have...