Thursday, April 30, 2015

Patterns ending in 25...

Middle schooler playing on calculator observes


1) What can we do to make this a teachable moment?
2) To which of the Mathematical Practices does this relate?
3) Do you think it's important for students to describe the pattern both verbally and symbolically?
3) Algebraic derivation?
4) Extensions? Does the pattern continue into 3 digits e.g., 105²=11025=110|25, 235²=55225=552|25, 23•24=552
Does the pattern eventually break down?

Sunday, April 26, 2015


Not exactly a math story but...

My 7-yr old grandson was at bat today. The next pitch appeared to graze him and the umpire told him to take 1st base. He turned around and said that the ball hit his bat and not him. The shocked ump told him to get back in. Two pitches later, he walked anyway. There's a moral here somewhere...

Wednesday, February 11, 2015

Open-Ended 2nd-3rd grade PARCC-Type Challenge Activity

Child will either draw a diagram, be given grid paper (1"x1") or use a bucket of at least 30 unit tiles.

(a) Make the largest square you can from 18 small equal squares. Use the grid paper to show this.
(c) Any left over? If yes, how many? (d) Which of the following multiplication problems is your big square most like?
3x3? 4x4? 5x5?
(e) How many more squares do you need to make the next larger square? Draw it or use tiles.

This is just a springboard for your own ideas. Your reaction to this?
How would YOU word this type of question? Share!

Saturday, February 7, 2015

MathNotations Survey - Best Ed Reforms Over Past 25 Years

My tweet @dmarain on 2-6-15 has generated hundreds of views but no opportunity to freely exchange ideas. I thought about setting up a twitter chat but, for now,I've opted for my blog as the vehicle.

So here's the question which is trending ...

What changes in education over the past 25 yrs do you think have most impacted how children learn?

Since this blog focuses mostly on issues in *math* ed
I'll kick this off by suggesting

1) Increased communication in the math classroom. I favor a balanced approach of direct instruction and posing open-ended nonroutine problems requiring team effort. NCTM promoted the importance of greater student-student and student-teacher interaction in 1989 and this is far more evident in our classrooms today.

2) Technology of course but specifically which technologies have had the greatest effect on learning math skills and math concepts. As a math educator, the access to and strategic use of powerful graphing calculators has enabled students to solve traditional problems in a variety of ways (multiple representation), explore topics in greater depth and model data more efficiently.

Anyone remember great software like Green Globs from the early 90's? We've come a long way since then with interactive geometry and algebra software and apps and we're still just at the toddler stage!

Haven't even mentioned the many curriculum projects, Common Core, and assessments but opinions on their benefits should vary widely.

OK, your turn. I hope this prompt will encourage comments but that's up to you. If you'd rather use twitter or other social network sites let me know. A chat on twitter might be the way to go in 2015.

So what is your Top 5 List of most significant changes?

Wednesday, January 21, 2015

When is a rectangle an equilateral triangle?

As posted on ...

Diagonal of a rectangle has length 6 and makes a 30° angle with a side.
(a) Area of rectangle=?
(b) If diagonal has length d, area=?


(1) A moderate difficulty problem for SATs? Appropriate or too hard for a PARCC assessment with both parts?

(2) Should diagram be given or is drawing part of what's being assessed?

(3) Will some students recognize that the expression in terms of 'd' is the formula for the area of an equilateral triangle of side length d? If no one does then is it our responsibility to model and facilitate "connection-making"? Uh, yes ...

More interestingly, will some students realize that the rectangle divides into two 30-60-90 triangles which can be rearranged to form an equilateral triangle? Hence, the title of this post!

If we create this kind of environment in our classes it may happen. I think we're all conditioned to thinking that's only for the top honors groups,  and only for a few students. But, for me, helping ALL children discover and uncover the beauty of mathematics was my raison d'ĂȘtre for teaching. Idealistic perhaps but when that is lost, what's left?

Monday, January 12, 2015

How one 2nd grader knows his 7 Times Table!

As posted on twitter @dmarain today...

Question to 2nd grader: 7×6
How did you know that?
Easy --- 6 touchdowns! I know all my 7's!

1) So do you think this is about a real 7-yr old?

2) Would this be useful to many or just for girls/boys who watch a lot of football? OR

Is there a bigger issue here re the individual ways in which children learn? I think there are some HUGE implications here for teaching/learning in the Common Core and beyond...

3) All these "strategies" turning you off? Yearning for the good old days -- having children write their facts 10 times each or flash cards and memorization?

I have mixed emotions since I'm probably older than most of my readers but the anecdote above is real and it did work for this particular child! Further the child said, "I know some of my sixes too!" Missed PATs?? Maybe field goals will help with the 3s!!

Your thoughts?

Friday, January 9, 2015

Implement The Core: Quadratic Function SAT-Type Assessment

As posted on Twitter @dmarain...

The graph of f(x)=-(x-k)^2+h has one x-int and a y-int=-16. Coordinates of all possible vertices? Sketch graph(s).


(1) How do you feel about the "h,k switch" on an assessment? Would you revise it or leave it alone?
(2) Level of difficulty here? How do you think your students would perform? Let me know if you use it!
(3) Are you finding more of these types of questions in current texts? If not, what resources do you use to raise the bar?
(4) What if the question had asked for the PRODUCT of all possible x-intercepts? Better question for standardized assessments? Since the answer to this revised question is -16 do you think some of your students would ask if that's a coincidence? Why not ask them to check that -- Then GENERALIZE!

Thursday, January 8, 2015

BREAK THE CODE: 12-91-1305

As tweeted  on Twitter @dmarain today:

Break the code:12-91-1305
Then multiply these #'s by 4/3...
And you'll get my OBJective here!

Use contact form in sidebar to send me your answer/thoughts or leave a "hint" or question in Comments!