Math Arguments
Problems, Questions, and Puzzles to spark discussion and argument in the maths classroom.
Complicated Crossings.
Explain WHY this works for adding fractions.
Three very similar-looking, but very different, ideas.
Which of these apply here?
Which don't?
The Butterfly, aka., "Cross-Adding".
Cross-canceling.
Cross-multiplying.
Now that you've explored the WHY of this trick, do you still want to continue using it or will you use another method?
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internet
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