Tuesday, September 18, 2012

The Math of Khan Part 2 - Going through Khan Academy's Math program in an hour a day


Hours 3,4,5 and 6: Multiplication and Division

This unit was pretty long, somewhat boring but no real problems with the material or any accolades for that matter.  It was pretty much having students grind their way through multiplication and division problems with increasing numbers of digits.  The skill list looks like this:


  1. Basic Multiplication
  2. Multiplying 1-Digit Numbers
  3. Basic Division
  4. Multplying 3-Digits by 1 Digit
  5. Multiplication with Carrying
  6. 1 Digit Division
  7. Multiplying 3-Digits by 2 Digits
  8. Multi-Digit Multiplication
  9. Multi-Digit Division Without Remainders
  10. Multiplication and Division Word Problems
  11. Division without Remainders
  12. Division with Remainders
  13. Multi-Digit Division
  14. Multiplication and Division Word Problems 2
  15. Multiplying and Dividing Negative Numbers
  16. Decimals on the Number line 1

Summary:

Generally I found doing 3 x 2 multiplication in my head a little difficult although division wasn't that bad.  For anything more complicated I resorted to using scratch paper.  Again I wonder how necessary it is to be tested on large numbers as the work was more tedious than difficult and I didn't feel like I was applying any kind of extra knowledge so as I stated before I don't see how students would view this topic as anything other than a grind.  That said I don't know how you can avoid this kind of work (other than cutting back a bit on the number of digits) still I'd rank this topic as:

Practicality
Accuracy






To give you an idea of the amount of work need to complete the unit.   I answered about 350 questions in 4 hours to achieve mastery here.  So I was averaging about 41 seconds per question implying that multiplication is four or five times harder for me than division.  Who'd a thunk it.

Next week I'll start looking at fractions and decimals.

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