Unpacking mathematics – a geometry example

 Posted by  Geometry
May 102013
 
Unpacking mathematics - a geometry example

Engineers, mathematicians, and mathematics teachers all deal with mathematics but it is only the math teacher who talks about math to non-mathspeakers and initiate them to ‘mathspeak’. To do this, the math teachers should be able to ‘unpack’ for the students the mathematics that mathematicians for years have been so busy ‘packing’ (generalising and abstracting) so that these learners will learn to do the basics of packing by themselves. This is in fact the real job description of a mathematics [...]

A Geometric Model for the Lunch Date Problem

 Posted by  Geometry, Math videos
Mar 232013
 
A Geometric Model for the Lunch Date Problem

A mathematical model is an abstract model that uses mathematical language to describe and understand a situation. Here’s a nice video that presents a model for the Lunch Date Problem. The video below shows a step-by-step tutorial using SketchPad to build a geometric model of the problem. What is nice about this video is that it still leaves the solving to the students. The resulting geometric model leaves enough information for students to figure out a solution. The Lunch Date Problem [...]

Why do we ‘invert’ the divisor in division of fractions

 Posted by  Elementary School Math, Number Sense
Mar 172013
 
Why do we 'invert' the divisor in division of fractions

The easiest (and the most common) way to teach division of fractions is to just give the rule: To divide 5/8 by 2/3, just multiply 5/8 by the reciprocal of the divisor, 2/3. That is, 5/8 ÷ 2/3 = 5/8 × 3/2 = 5×3/8×2 = 15/16. If this is all we want our students to learn why bother teaching? I’m sure our students will be old enough to buy/download a calculator before they find themselves working on a problem that involves division [...]

Pentagon to Quadrilateral Puzzle

 Posted by  Geometry
Mar 112013
 
Pentagon to Quadrilateral Puzzle

Puzzles involving cutting shapes and forming them into different shapes helps reinforce the idea that area do not necessarily change with change in shape. It is also a good activity for developing visualisation skill and spatial ability. The puzzle below is from one of the leaflets at the booth of Japan Society of Mathematical Education last ICME 12 in Seoul, Korea. The original puzzle is suited for Grade 4. The instruction was to cut the pentagon along the dotted lines and then [...]

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