Posted in Curriculum Reform, Elementary School Math

English edition Japanese Grades 1- 6 Math textbooks 50% off until September

Last year I had the chance to do a few days work for a Japanese Mathematics textbook series translated in English. I just received an e-mail from one of the editors that the publisher is selling the books at 50% off. It will only cost about US$75 for the set of 11 books until September 2011. After September the set will cost about $US150. 00, the latest edition. I don’t have a copy yet of the books so I cannot show here a page  but my colleague and I did some editing for Grades 5 and 6 and we think that the Japanese really have a very different approach in teaching mathematics be it in textbooks and in teaching. There’s a very strong emphasis on developing mathematical thinking (I saw several lesson study demonstration teaching while there. Our Institute also had a 5-year math and science teaching project with Japanese educators). The solutions shown and the structure of the books model how students in that grade level think and would approach the problems. The books are a product of years of doing lesson  study in mathematics. I love the section “Let’s think about how to…”

The schools where you teach may already have a prescribed textbook but you will have a great resource in designing your instruction with this set. Your school might even decide to use the textbooks.

For ordering, please send your order to Mr. Serizawa: Continue reading “English edition Japanese Grades 1- 6 Math textbooks 50% off until September”

Posted in Algebra, Curriculum Reform

What is algebra? Why study it?

I’m doing some  literature review for my research and I came across this article by L.A Steen in Middle Matters. He was arguing about the Algebra for All standard in the US and part of the article includes description of what is algebra. I thought I should share them in this blog because it is something very important teachers should be aware of when they teach algebra or what they conceive what algebra is and for. Oftentimes, when students ask what algebra is and what they are going to need it for, teachers lazy answer is “Algebra is just like your math in the grades only that this time you work with letters instead of numbers!”

  1. Algebra is the language of mathematics, which itself is the language of the information age. The language of algebra is the Rosetta Stone of nature and the passport to advanced mathematics (Usiskin, 1995).
  2. It is the logical structure of algebra, not the solutions of its equations, that made algebra a central component of classical education.
  3. As a language, algebra is better learned earlier and harder, when learned later.
  4. In the Middle Ages, algebra meant calculating by rules (algorithms). During the Renaissance, it came to mean calculation with signs and symbols–using x‘s and y‘s instead of numbers. (Even today, lay persons tend to judge algebra books by the symbols they contain: they believe that more symbols mean more algebra, more words, less.) I think that many algebra classes still promote this view.
  5. In subsequent centuries, algebra came to be primarily about solving equations and determining unknowns. School algebra still focuses on these three aspects: employing letters, following procedures, and solving equations. This is still very true. You can tell by the test items and exercises used in classes.
  6. In the twentieth century algebra moved rapidly and powerfully beyond its historical roots. First it became what we might call the science of arithmetic–the abstract study of the operations of arithmetic (addition, subtraction, multiplication, etc.). As the power of this “abstract algebra” became evident in such diverse fields as economics and quantum mechanics, algebra evolved into the study of all operations, not just the four found in arithmetic.
  7. Algebra is said to be the great gatekeeper because knowledge and understanding of which can let people into rewarding careers.
  8. Algebra is the new civil right (Robert Moses). It means access. It means success. It unlocks doors to productive careers and gives everyone access to big ideas.

And I like the education battle cry Algebra for All. Of course not everyone is very happy about this. Steen for example wrote in 1999:

No doubt about it: algebra for all is a wise educational goal. The challenge for educators is to find means of achieving this goal that are equally wise. Algebra for all in eighth grade is clearly not one of them–at least not at this time, in this nation, under these circumstances. The impediments are virtually insurmountable:

  1. Relatively few students finish seventh grade prepared to study algebra. At this age students’ readiness for algebra–their maturity, motivation, and preparation–is as varied as their height, weight, and sexual maturity. Premature immersion in the abstraction of algebra is a leading source of math anxiety among adults.
  2. Even fewer eighth grade teachers are prepared to teach algebra. Most eighth grade teachers, having migrated upwards from an elementary license, are barely qualified to teach the mix of advanced arithmetic and pre-algebra topics found in traditional eighth grade mathematics. Practically nothing is worse for students’ mathematical growth than instruction by a teacher who is uncomfortable with algebra and insecure about mathematics.
  3. Few algebra courses or textbooks offer sufficient immersion in the kind of concrete, authentic problems that many students require as a bridge from numbers to variables and from arithmetic to algebra. Indeed, despite revolutionary changes in technology and in the practice of mathematics, most algebra courses are still filled with mindless exercises in symbol manipulation that require extraordinary motivation to master.
  4. Most teachers don’t believe that all students can learn algebra in eighth grade. Many studies show that teachers’ beliefs about children and about mathematics significantly influence student learning. Algebra in eighth grade cannot succeed unless teachers believe that all their students can learn it. (all italics, mine)

I shared these here because in my part of the globe  the state of algebra education is very much like what Steen described. You may also want to read about the expressions and equations that makes algebra a little more complicated to students.

L.A Steen is the editor of the book On the Shoulder of Giants, New Approach to Numeracy, a must read for teachers and curriculum developers. The book is published by Mathematical Sciences Education Board and National Research Council.

Posted in Elementary School Math

How should students understand the subtraction operation?

Studies show that students whose understanding of subtraction is only to take away will have difficulty learning other mathematical concepts.

There are three ways by which subtraction can be understood: (1) Taking Away, (2) Difference, and (3) Inverse relation to addition operation. Pupils’ first experience with subtraction involves taking away. The dash sign means minus and minus is taken to mean ‘take away’.

Subtraction as ‘taking away’

Here are formats of subtraction tasks that involve taking away:

  1. Marco has 12 twelve marbles. He gave 5 to his friend Precy. How many does he have left? (This problem is represented by the equation, 12 – 5 = ____.)

    subtraction as taking away
  2. Marco has 12 marbles. He gave some to his friend, Precy. If he had 7 marbles left, how many did he give to Precy? (This problem is represented by the equation, 12 – ____ = 7.)
  3. Marco gave his friend 5 marbles. If has 7 marbles left, how many did he have at the start? (This problem is represented by the equation,  ____ – 5 = 7.)

Problem situation number 3  require subtraction representation but is actually an addition problem because the solution involve adding 5 and 7 instead of doing subtraction.

For most students this is all they understand about subtraction — to take away. This is probably because the use of subtraction in many daily life situations use this meaning. To compound this situation, many of the subtraction tasks in textbooks are also of this type. Very few, if there is any, will include problems that supports the development of the other meaning of subtraction.  And when for a long time all one know about subtraction is to take away, it would be very hard to accept other meanings. Studies show that students whose conception of subtraction is only to take away will have difficulty learning other mathematical concepts.

Continue reading “How should students understand the subtraction operation?”

Posted in Geogebra, Geometry

Constructing polygons with equal area

The power of GeoGebra lies not only for demonstrating a concept but more so for creating a situation where students are made to think, solve problems, and reason mathematically. Here is a sample lesson on how this can be done. The lesson involves the concept of area of triangles and constructing parallel lines applied to problems involving preserving areas of polygons. The most ideal situation is for students to explore on the applets individually or in small group. If this is not possible and the students have no computers, the applets can be projected. The teacher can then call a students or two to explore the applets. The idea is to stimulate students’ thinking to think of explaining why the transformations of the shapes are possible. The students should have a triangle rulers or straight edge with them. The lesson will not be complete if the students cannot devise a procedure for transforming a triangle into other polygonal shapes with the area preserved.

The following applet may be used in the introductory activity to teach about triangles with equal areas. Click here to explore. The applet shows that all triangles with equal base and have equal heights or altitude have equal areas. That’s pretty obvious of course.

The next applet is more challenging but uses the same principle as the first.
Depending on the previous knowledge of your students you can give this second applet right away without showing the first applet on triangles. Click here or the worksheet below explore and answer the problem.

Extension problems using the same principle about area of triangles.

triangle rulers
  1. Given a triangle, construct the following polygons equal in area to the given triangle using triangle rulers and pencil only:  a) parallelogram; b)trapezoid; c) hexagon. (There’s nothing that should prevent you from using GeoGebra to construct them.)
  2. The Rosales and Ronda families are not very happy with their piece of land because of the narrow corners. Help this family to draw a new boundary line without changing the land area of each family.

I will deprive you of the fun if I will show the answers here right away, won’t I?

I will appreciate feedback on this lesson.