Thursday, April 26, 2012

When is 11 1/9% equal to 10%=?UTF-8?B?Pw==?=

If # of  left-handers are 11 1/9% of right-handers, what % of total pop are left-handed? (disregard ambidextrous)

Questions for Middle School Teachers
1) At what grade level would this kind of problem be introduced?
2) Would you allow use of calculator here or expect students to change 11 1/9% to 100/9% and 111 1/9% to 1000/9%? More importantly, am I out of my mind to think that students at any grade level including secondary would do this!
3) WHAT ARE THE BIG IDEAS HERE?
4) WHERE DOES THIS TYPE OF QUESTION FIT INTO CORE STANDARDS?

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2 comments:

Alana Gilliam said...

I teach 8th grade and we discuss something similar, but to say my students would figure that out no way. They would probably have dear in headlights look.

Dave Marain said...

Sadly most secondary students and adults would have that look. There are several issues here:
1) Developing earlier facility with mixed numerals and improper fractions. Yes, I want 3rd and 4th graders to visualize/conceptualize that 2 3/4 is the same as eleven quarters in a pizza and 11 quarters equals $2.75 BUT AFTER THAT THEY NEED TO CONVERT MENTALLY IN A FEW SECONDS. Of course, not all will be abke to at the same time but THERE IS NO SUBSTITUTE FOR SHOOTING 500 FREE THROWS A DAY IN THE GYM!
2) Ability to find the ratio of 2 percents by ignoring the % symbol since both are ÷ by 100
3) KNOWING WHEN TO TURN CALCULATORS OFF AND BRAINS ON!