(no subject)

[tinyjo]

So, if we're going to buy expensive schemes to teach children maths, can the providers please make sure that the activities make sense and aren't, you know, wrong or anything.

Say the number: four thousand, seven hundred and eighty-three. Ask children in their groups to write this in figures. Write it on the board to check: 4783. What is the lowest number you can add so that all four digits change? Allow 3 or 4 minutes to try this, then take feedback. (1111 is the lowest number that can be added so that all four digits change, making 5894.) Will this always be the lowest number? Can you find a 4-digit number where all four digits can be changed by adding a lower number? Ask children to explore this, starting by finding different types of number (e.g. multiples of 10 or 100) where a lower number can be added. Ask them to write some general rules (e.g. if the number ends in 9, then the lowest number that can be added to make all four digits change is 1101.)

Just.... No, don't do that! I can't even think of an interpretation that might make that make sense.

Comments

[tortipede.livejournal.com]

Thinking this through more, and re-reading everybody's comments, I think what they're trying to do is to move children from a mathematical worldview that doesn't take account of carrying, where 1111 would be the only possible answer, to one that does — using, as phlebas said, a sort of vaguely scientific-ish experimentation approach. They're meant to start off with 1111 and arrive at 217, discovering the Joy of Carrying for themselves along the way — at least, that's how I read the business about 9 and 1101. But by implying that 1111 is the correct answer rather than a good starting point, they've neither said what they really meant nor meant what they said. Yesno?

[phlebas.livejournal.com]

I think you're right.

[celestialweasel.livejournal.com]

Hmm. I think you're right, but I seem to recall that in the happy days of new maths (circa 1970) carrying was taught through the medium of Deans (probably not spelt that way and can't be bothered to Google) blocks - along with bases and positional notation (or whatever you call it) - can you really separate the 3 concepts very much?

[tinyjo.livejournal.com]

Ah, that's interesting - it's so badly worded that I didn't realise what the teaching point might be! I was so blinded with rage at the categorical statement of wrong at the start :)