STI Course A Closer Look at Singapore Math by Yeap Ban Har

June 2010
usinganchorproblems
insingaporemath
Yeap Ban Har
Scarsdale Teachers Institute
New York USA

Problem 1
Arrange cards numbered 1 to 10 so that the trick shown by the instructor can be done. In this problems, students get to talk about the positions of the cards using ordinal numbers. They get to use ordinal numbers in two contexts – third card from the left and third card from the top. The problem itself is too tedious to describe using words. Just come for the institute next time round!

Teachers solved the problems in different ways.

The above is the solution. What if the cards used are numbered 1 to 9? 1 to 8? 1 to 7? 1 to 6? 1 to 5? 1 to 4?

Problem 2
This is a game for two players. The game can start with any number of paper clips, say, 24. The rule is that a player removes exactly 1 or 2 clips when it is his / her turn. The winner is the player who removes the last lot of paper clips. Find out a way to win the game.

It turns out that the winning strategy is to leave your opponent with a multiple of three. What if the rule is changed to removing exactly 1, 2 or 3 clips? The winning strategy is to leave your opponent with a multiple of four. Did you notice a pattern?
Problem 2
In this anchor problem and its variant(s), the concept of multiples emerges. Anchor problem does that – to emerge a mathematical concept.

Problem 3
The initial textbook problem was changed into the second one. Anchor problems and its variants allow students to encounter a range of problems with mathematical variability (Dienes). In this case students encounter both arithmetic and algebraic problems, and also problems with continuous as well as discrete quantities. Although both problems involve the same bar models, the mathematics involved are different.

273
Najib
Pascal
297
Goggle
Gittar

Problem 4
Mrs Liu spent 1/5 of her monthly salary on a handbag,  of the remainder on a vacuum cleaner and saved the rest. She saved $1890. Find her monthly salary.
= half
= three-eighths
= four-sevenths
The anchor problem was varied systematically so that students get to learn different skills in bar modeling. Notice the different bar modeling skills needed to solve the problem when  is changed from half to three-eighths to four-sevenths.
This problem is taken from a Singapore school’s mock examination to prepare students for the national examination at the end of grade six.

Three methods to solve the third problem.

Problem 5
Think of a 4-digit number, say, 1104. Jumble the digits up to form a different number, say, 0411. Fin d the difference between the two numbers (1104 – 411). Write the difference on a piece of paper. Circle any digit. Tell me the digits you did not circle and I will tell you the one you circled.

How can you tell what the circled number is given the numbers which are not circled?

Problem 6
Piece the pieces together so that two adjacent values are equal. Initially students can be asked to simply piece any two pieces together. Later they can be asked to form a single ‘snaking’ figure. Finally they can be challenge to form a square.

Problem 7
Place digits 0 to 9 in the five spaces to make a correct multiplication sentence – no repetition. 2-digit number multiplied by 1-digit number to give a 2-digit product.
x

Why are there so few odd products?

Summary
anchorproblems

Roles
To emerge the idea of multiples
To provide opportunities to use ordinal numbers in varied situations
To provide opportunity to solve arithmetic and algebraic problems that involve continuous and discrete quantities
To provide opportunity to learn different skills in using bar models
To provide opportunity to do drill-and-practice while

Participants working through anchor problems they created.
workshopactivity

References
theoriesandmodels

Polya
Problem-Solving Stages
Understand
Plan
Do
Look Back
Polya

Newman
Difficulties in Word Problem Solving
Read
Comprehend
Know Strategies
Transform
Do Procedures
Interpret Answers
Newman

Dienes
Principle of Variability
Mathematical Variability
Perceptual Variability
Dienes

Krutetskii
The ability to pose a ‘natural’ question as a form of mathematical ability
Krutetskii
Krutetski (1976). The psychology of mathematical abilities in school children. Chicago, IL:
University of Chicago.

Big Ideas
Visualization
Patterning
Number Sense
Metacognition
Communication
Big Ideas

Beliefs
Interest
Appreciation
Confidence
Perseverance
Monitoring of one’s own thinking
Self-regulation of learning
Attitudes
Metacognition
Numerical calculation
Algebraic manipulation
Spatial visualization
Data analysis
Measurement
Use of mathematical tools
Estimation
Mathematical Problem Solving
Reasoning, communication & connections
Thinking skills & heuristics
Application & modelling
Skills
Processes
Concepts
Numerical
Algebraic
Geometrical
Statistical
Probabilistic
Analytical
Mathematics Curriculum Framework

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STI Course A Closer Look at Singapore Math by Yeap Ban Har

by Jimmy Keng on Jun 06, 2010

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STI Course A Closer Look at Singapore Math by Yeap Ban Har — Presentation Transcript