Sunday, March 30, 2014

A Data-Based Percent Problem for the New SAT and Common Core

The MathCast below is a more sophisticated % problem which requires processing several pieces of data expressed in percent form. Students have to make sense of the information and  develop a model to represent the data. Both a tree model and a table/spreadsheet approach are demonstrated.

These are the kinds of data-based applications which will become a central theme of the newer assessments from PARCC, SBAC and the College Board.

Sorry, you'll have to watch the video to see the problem but I'll give you a glimpse:

70% of the left-handed students surveyed were boys...

Watch "SAT/Common Core Data-based Percent Challenge" on YouTube - SAT/Common Core Data-based Percent Challenge:

Also, pls let me know if these MathCasts are blurry.

Monday, March 24, 2014

40% of 9th graders play sports...Math Challenges for the Old/New SAT and the Common Core

David Coleman of the College Board has stated that ratios, percents, etc., will be an important focus of the new SAT, particularly in an applied setting.The MathCast below demonstrates a classic medium-hard percent word problem which should continue on all of our "new" assessments.

Watch "40% of the 9th grade... Percents,New SAT and…" on YouTube-40% of the 9th grade... Percents, the New SAT and…:

I encourage all my readers to offer constructive criticism re both the content and the technology of these videos and suggest topics/problems for future MathCasts.

Wednesday, March 19, 2014


A hard adjustment for parents/educators who were raised as I was on traditional algorithms. Of course, understanding the rule for multiplying fractions DOES NOT mean students should use this to get the result.

Teaching conceptually is fundamental to the Mathematical Practice Standards of the Common Core. BUT this should be BALANCED with traditional methods. Current thinking is that the way we learned may be far more efficient but it leads one to think of math as just a set of meaningless rules. Kind of like a "black box." I see the need for both.

After watching this MathCast you'll probably conclude this is way too confusing for students not to mention adults! Just remember, some of that confusion results from sloppy drawings and carelessly worded explanations. I'm definitely guilty of both!

Watch "SHOWING one-third of three-fourths vs Traditional" on YouTube -

Sunday, March 16, 2014

5^(2x)=4; Find value of 5^(3x-1) Non-Calculator SAT-Type

These types of more challenging exponent problems requiring strong manipulative skills will probably not go away on the New SAT!
And on the NON-CALCULATOR section!

You have to watch the video to see the solution!

Watch "5^(2x)=4; Non-calculator exponent SAT-Type Problem" on YouTube - 5^(2x)=4; Non-calculator SAT-Type Problem:

Saturday, March 8, 2014

4% of 8% of 16x is what % of 2x? New SAT, Common Core and Percents, Pt.1

A classic SAT math challenge that will probably not go away on the new SAT coming in 2016. And just imagine if calculators are not allowed for this!

Watch "4% of 8% of 16x is what % of 2x? New SAT, Common Core and Percents Pt 1" on YouTube -

Tuesday, March 4, 2014

Similar Figures MathCast - The Big Ideas and the Common Core

Watch "Similar Figures - The Big Ideas and the Common Core" on YouTube -

This 20 min video develops the Basic Proportionality Theorems re perimeters and areas of similar figures. Multiple representations and teaching conceptually are demonstrated with a strong emphasis on visualization.

Feedback would be helpful and appreciated...