median
don steward
mathematics teaching 10 ~ 16

Sunday, 25 November 2007

what's the point?

I liked a story of a young child who, when asked what the dot was in a decimal number, suggested that it was a "cash point"






perhaps we should revert to the historical vertical line instead of a point (that way at least you might see some trace of it in student's work) to mark the border between wholes and deci-parts of wholes

three interesting questions for discussion are:
  • what is 4.6 + 3?
  • what is half way between 3.1 and 3.2?
  • what is 1 - 0.4?
these, with supplementary questions can occupy quite a lot of time ... with some heated debate (with hopefully satisfactory conclusions)

hidden noughts and decimal points are sometimes helpful (pointers)...

"can you see the hidden decimal point after the 3?"
"nope"
"well that's because it isn't there, but it is kind of isn't it?"
"eh?"
.....

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