Tuesday, September 11, 2012

Buying Kiwi

Today's math lesson- buying kiwi at the store.
(I'm often asked how you teach math when unschooling)

 Me- So if 1 kiwi is 38 cents and a 6-pack is $2.77, which is the better deal?

Josh- I can't multiply 38.... ...

M- Well, we could round it up to 40 cents. That would be easier to multiply in your head, right?

J- Yeah. Let's see, 6x4 is the same as 6x2x2 so 6x2 is 12.... and 12x2 is 24 so 6 kiwis would be $2.40.

M- Almost, don't forget we added 2 extra cents to make it easier.

J- Oh yeah! So that's 12 extra cents, and 40-12 is.....(struggling)

M- Do one place value at a time.

J- 40-10 is 30, 30-2 is 28. So $2.28.

M- So should we buy 6 individual or the pack?

J- Individual.

 M- Good job, Buddy.

No comments:

Post a Comment