Speed and Rate Problems

song chart memes

Rate problems provide some of the biggest challenges to students and adults. These come from Problem-Solving Processes in Mathematics -6 B by Fabian Ng.

  1. At 10:15 am, a car left Town X for Town Y at an average speed of 86 km/h, while a truck left Town Y for Town X at an average speed of 74 km/h. At 3:15 pm, the two vehicles were 12 km apart. How far apart were the two towns?
  2. At 10:30 am, a cyclist started traveling on a road at an average speed of 60 km/h. At 2:30 pm, a motorist started from the same place, traveling on the same road. If the motorist took 4 hours to catch up with the cyclist, find his average speed.
  3. The distance from Town P to Town Q was 312 km. Winston started from Town P at an average speed of 76 km/h. He maintained this speed for 2 hours before increasing it by 4 km/ for the rest of the journey to Town Q.
  4. a. how long did he take to complete the whole journey?
    b. What was his average speed from Town P to Town Q?

Can you draw a model or diagram to illustrate each of these problems?

(Answers next week!)

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Singapore Math – Old School

old_school
Old School claims to be Singapore’s #1 Primary School site. From the site:

Old School aims to be the premier resource for FREE educational material from Singapore, especially Singapore Math and Singapore Science. We have a large database of test questions and assessments and are always adding new content.

Currently, they offer test papers as well as the ability to take tests online in English, Mathematics and Science. Registering on the site allows you to track your progress on the online tests (usually the “A” part of each). Best of all, you can search the questions by topic and select questions with either a multiple choice or free-response format.

As an example, the Primary Four 2009 Mathematics page offers:

  • 3  Continual Assessment 1 tests
  • 4  Mid-Year Examination tests
  • 3  Continual Assessment 2 tests
  • 4 End Year Examination tests

That include the following topics (with the percentage of questions):

  • Angles (7%)
  • Area and Perimeter (8%)
  • Decimals (4%)
  • Factors and Multiples (6%)
  • Four Operations (22%)
  • Fractions (18%)
  • Geometry (2%)
  • Graphs (2%)
  • Measurement (7%)
  • Non-Standard Questions (6%)
  • Perpendicular and Parallel Lines (4%)

The majority of mathematics papers are a 2 out of 4 on the site’s scale of difficulty. There were some assessments with a difficulty rating of 1.

Here’s a problem from the 2009 Primary Four End Year Assessment for your enjoyment:

Fill in the missing number.

108 x 99 = 110 x 99 + 10 x 99 – ( ? ) x 99
  1. 8
  2. 2
  3. 12
  4. 228
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Intermediate Word Problem

Published in Singapore, Challenging Problems in Mathematics for Primary Schools: Intermediate by Dr. Y.H. Leong is a series specially written to provide enrichment activities for students.  The intermediate edition is designed for Primary 4 & 5 students.

Enjoy!

A farmer planted 22 rambutan trees in a straight row. The trees were spaced out equally. If the distance between the 3rd tree and the 10th tree was 42m, find the distance between the 2nd tree and the 22nd tree.

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Comparing Singapore Math Materials: Workbooks

In Part 1 and 2,  I shared examples from the Teacher’s Guides and Textbooks from four sets of materials used in Singapore and the United States. The materials are all from the third grade level:

  1. Primary Mathematics U.S. Edition (2003)  from SingaporeMath.com
  2. Primary Mathematics Standards Edition (2008)  from SingaporeMath.com
  3. My Pals Are Here Maths (2007) obtained in Singapore from Marshall Cavendish
  4. Shaping Maths (2007) obtained in Singapore from Marshall Cavendish

Following are the practice pages from each workbook that correspond with the lesson on addition within 10,000 that introduces regrouping in the hundreds. As before, each thumbnail links to a full-sized file. Once again, there are minimal differences between the U.S. and Standards editions of Primary Mathematics.  Problem #1 changes pictures from towels hanging on a clothesline to boats. Problem #2 has one small change. The equation for  letter B changes from  4107 + 5 to 4105 + 5. Finally, on problem #4, “Weihua” becomes “Will” U.S. Edition Workbook 3A: USp25USp26USp27 Standards Edition Workbook 3A: STp48STp49STp50 The My Pals Are Here Workbook is perforated and 3 hole punched. Perforated pages would be a great change to make to the Primary Mathematics workbooks! Neither My Pals Are Here nor Shaping Maths have any word problems tied to this practice lesson, in fact, there are very few word problems in the books at all. My Pals Are Here Workbook 3A Part 1: MPAHp29 MPAHp30 Shaping Maths Activity Book 3A part 1: SMp31 SMp32 Were you expecting less practice in the materials from Singapore?

Parts in the series:

Part 1 – Teacher’s Guides

Part 2 – Textbooks

Part 3 – Workbooks

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Creative Thinking Problems

I had coffee with another fan of Singapore Math this week and he loaned me some supplemental materials from his travels to Popular Books in Singapore. These two problems come from Accelerated Learning Primary Mathematics 3 by Ching Kheng Huat published in 1999.

The front page states:

In this book, “Accelerated Learning” fosters in pupils the ability to learn faster, to remember more and to think creatively.

The Ministry of Education has initiated IT in education for pupils. To make time for IT, pupils need to learn faster to cover the syllabus. And this requires ACCELERATED LEARNING – a new dimension in pedagogical skills. MOE has also emphasized the need to develop CREATIVE THINKING, which we have incorporated in this book.

The book has seven pages of “Infographic  Images” at the beginning (visual dictionary of terms), then practice pages for 12 units. Each unit of six to seven pages has:

  1. two worked examples
  2. multiple choice practice
  3. short answer practice
  4. problem sums practice
  5. creative thinking problem (one or two)

Here are the Creative Thinking problems from the unit on fractions:
Fractions

And a Creative Thinking problem from the unit on time:

It takes 4 h 15 min to repair 3 computer. Repairing a radio takes 47 minutes less that the time needed to repair a computer. If a worker works 9 hours a day, he needs to complete repairing 10 items that can include both computers and radios. How many computers can he repair if he needs to repair as many computers as possible?

Do you feel that these problems will help students “develop creative thinking” ?

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Comparing Singapore Math Materials: Textbooks

In Part 1, I shared some examples from the Teacher’s Guide from four sets of materials used in Singapore and the United States.

The materials are all from the third grade level:

  1. Primary Mathematics U.S. Edition (2003)  from SingaporeMath.com
  2. Primary Mathematics Standards Edition (2008)  from SingaporeMath.com
  3. My Pals Are Here Maths (2007) obtained in Singapore from Marshall Cavendish
  4. Shaping Maths (2007) obtained in Singapore from Marshall Cavendish

Following are the pages from each textbook unit on addition within 10,000  that introduces regrouping in the hundreds. As before, each thumbnail links to a full-sized file.

There are minimal differences between the U.S. and Standards editions. The Standards edition is in color and there are two additional prompts asking students to estimate their answer first, then check for reasonableness. The first example shows regrouping in the hundreds. Problems 1-5 ask students to recall addition with regrouping the ones or tens or hundreds.

U.S. Edition Textbook 3A:

USp24 USp25 USp26

Standards Edition Textbook 3A:

STp50 STp51 STp52

My Pals Are Here includes two pages of instruction, another page with directions to a game and a final page exploring regrouping in the hundreds. Problem 5b on page 29 is the only problem that demonstrates  regrouping in both the ones and hundreds places,  although students are only asked to find the missing ones value in one addend.

Note the example #2 on page 29 that spells out the concept in words  (5 hundreds + 8 hundreds). This is a great reminder of how teachers can model this concept in a classroom and is included in the Teacher’s Guide for Primary Math both U.S. and Standards editions ( 7 ones + 5 ones = 1 ten 2 ones).

My Pals Are Here Textbook 3A:

MPAHp28 MPAHp29 MPAHp30 MPAHp31

The Shaping Maths lesson is two pages of slightly more abstract description than My Pals Are Here. Place value disks are used instead of images of base-10 blocks.

Shaping Maths Coursebook 3A:

SMp32 SMp33

Which materials would you choose for your third grade classroom? Share your opinion in the comments!

Parts in the series:

Part 1 – Teacher’s Guides
Part 2 – Textbooks
Part 3 – Workbooks

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Comparing Singapore Math Materials: Teacher’s Guides

First in a three-part series

I thought it might be interesting to provide examples of how a lesson is presented in four different sets of Singapore Math materials. Part 1 compares the materials where a lesson begins – the Teacher’s Guide. The rest of the series will include textbooks and workbooks.

All four sets of materials are listed below. The two editions of Primary Mathematics are currently in use throughout the United States. My Pals Are Here and Shaping Maths are currently in use in Singapore.

This overview doesn’t include the Math in Focus series by Marshall Cavendish and exclusive United States distributor Great Source (A division of Houghton Mifflin Harcourt)  which will be available soon in the United States.  Representatives at the NCTM Conference in Washington, D.C. stated that the Math in Focus content is based on the  Singaporean edition of  My Pals Are Here, with U.S. money and measurement the main additions. A listing of key topics can be found on the Great Source site.

The materials are all from the third grade level:

  1. Primary Mathematics U.S. Edition (2003)  from SingaporeMath.com
  2. Primary Mathematics Standards Edition (2008)  from SingaporeMath.com
  3. My Pals Are Here Maths (2007) obtained in Singapore from Marshall Cavendish
  4. Shaping Maths (2007) obtained in Singapore from Marshall Cavendish

Most people will display the cover of a book. You get the title, authors and little else. The back of the book,  however, contains more interesting information. (Exception? The Primary Mathematics-U.S. Edition) These are from the 3A Teacher Guides and provide a brief overview of each series. For your reading ease, each thumbnail links to a full-sized file.

PMUS

PM-St

MPAH

SHAP

For comparison, I will be using the first lesson in the 3A materials from the unit on addition within 10,000  that introduces regrouping in the hundreds. All materials use the term “renaming” except My Pals Are Here, which uses “regrouping”.

Below are the names, pages and the stated objectives for the lesson from the corresponding Teacher’s Guide along with one page as an example:

PMUSp22

Primary Mathematics-U.S.: Adding Ones, Tens, Hundreds and Thousands (p. 22)

  • Add numbers within 10,000.

PMStp74

Primary Mathematics-Standards: Adding Ones, Tens, Hundreds and Thousands (p. 74)

  • Review of addition of numbers up to 3 digits.
  • Adding thousands with another number up to 4 digits with renaming once.

MPAHp40

My Pals Are Here: Addition With Regrouping in Hundreds (p. 40)

  • Add two 4-digit numbers with regrouping in hundreds using concrete representation.
  • Show regrouping of hundreds to thousands and hundreds.
  • Carry out vertical column addition by adding the hundreds first then the thousands with regrouping in the hundreds place
  • Add without place value charts.

SHAPp56

Shaping Maths:Addition (p. 56)

  • To add 4-digit numbers with renaming once.
  • To add 4 digit numbers with renaming more than once.

Both My Pals Are Here and Shaping Maths have a larger sized Teacher’s Guide (A4 size). This allows the publisher to include each page from the textbook, surrounded by:

My Pals Are Here: instructional objectives, instructional procedures, key concepts, materials, additional activities, individual work, heuristic for problem solving and thinking skills

Shaping Maths:  objectives, lesson, materials, classroom organisation, vocabulary, general learning difficulties, IT, notes and textbook practice

The Teacher’s Guide for Primary Mathematics – Standards provides much more guidance.  The layout of the material is more familiar to most teachers and looks a bit more like a typical American teacher manual.  Although the Standards Edition provides California Standards, it would be easy to correlate these to another state’s standards. As a design, I like the spiral binding that allows the book to lay flat.

As we will see in the rest of the series, you should not choose a set of materials based on the Teacher’s Guide alone.

Next in the series:

Part 2 – Textbooks
Part 3 – Workbooks

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Math Problem Comparison

Teachers often ask, “What’s the difference between (the textbook I’m using now) and Singapore Math textbooks?” While there are many answers, I’d like to direct you to a resource that has been pointing out some differences  for over a year.

Once a week, Lefty (as in left-brained) over at Out In Left Field posts assignment comparisons between either a traditional math program or Singapore Math and various reform math textbooks.

From the original post:

Math problems of the week: Reform Math vs. other math

We’ll pair up a specific assignment drawn from this set with a specific assignment drawn either from a traditional series like McGraw-Hill, or from the foreign series most popular in America: Singapore Math.
I’ll try to pick assignments that take place at approximately the same point in the school year.  For example, I might choose two assignments from the first few weeks of first grade, or from the last few weeks of second grade, or from approximately 2/3 of the way into third grade.

At the end of many posts are some thought provoking Extra Credit questions. Some examples:

  • Which problem set involves more rote repetition of a given algorithm?
  • Which problem set is more accessible to children with language impairments?
  • Discuss how the two problem sets reflect the cultural and political differences between American and Singaporean societies.

Although many of the sample problems come from Singapore Math, there are also comparisons to traditional math books from the 1920s.

Enjoy!

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Grade 6 Word Problem Solutions

Earlier this month, I posted the following problem from a Nanyang Primary School 2007 Preliminary Examination I found at MissKoh.com:

A mixture, weighing 100 kg is made up of 2 chemicals A and B in the ratio of 7:3. When some volume of Chemical A evaporates, the content of Chemical A is reduced to 60% of the new mixture. What is the mass of the mixture now?

I thought I’d share how my son worked the problem:

chemical wp

He knew that if he multiplied 40% x 2.5, he’d get 100% so:

2.5 x 30 kg = 2.5 x 40%

75kg = 100%

I used a different drawing for “after” :

chem after

How did you solve the problem?

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World Metrology Day


I know you’re on the edge of your seat.

World Metrology Day is celebrated annually on May 20, the anniversary of  the international agreement on units of measurement finalized at the Metre Convention in Paris, France in 1875.

World Metrology Day (WMD) commemorates the signing of the treaty and it is a day when all the countries in the world that enjoy the benefits of a single, coherent system of measurements, traceable to the International System of Units (SI), celebrate the scientific, technological, and economic achievements that this treaty has enabled for more than a century.

There are only 3 countries in the world that have not officially recognized the metric system: Liberia, Myanmar, and the United States.

Great news for students struggling to remember how many ounces in a pound, feet in a mile, or cups in a gallon. According to Elizabeth Gentry of the National Institute of Standards and Technology(NIST):

The United States is undergoing a subtle transition to the International System of Units (SI), commonly known as the metric system.

Learn about events in Gaitherburg, MD and Boulder, CO as well as celebrations around the world at the official WMD2009 site.

You were wondering: “What is Metrology?”

From Coastal Calibration Laboratories:

Definition 1): Metrology is the science of measurement.

Definition 2): Metrology is the science of weights and measures used to determine the conformance of an item to technical requirements. Metrology also includes the development of standards and systems for absolute and relative measurements.

Want to learn more about Metrology?

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