Tuesday, September 11, 2012

Should Algorithms Be Taught in School?

                 According to the 2009 scores from the Program for International Student Assessment (PISA) report, which compares the knowledge and skills of 15-year-olds in 70 countries around the world, the United States performed below –average in mathematics and was ranked 25th out of 34 OECD countries.  In addition, “The United States spends more per student, on average, than other countries. The report notes that countries like Estonia and Poland perform at about the same level as the United States, while spending less than half the amount per student (USA Today,December 7, 2010).”  Does this information tell you anything about the way mathematics is taught in the United States?  In my opinion, these results signify a dire need for change in the education system of the United States.






Many teachers in America resort to the traditional algorithm when teaching number concepts.  Asking students to memorize procedures and rules before they have developed a conceptual understanding of addition, subtraction, multiplication, division, and fractions is putting students at risk.  As students rely on their memory of a series of rote steps, they are losing the meaning for the concept, are not applying estimation or place value and are working against their number sense.  Many students develop misconceptions because they either: confuse the algorithms, make computational mistakes within the algorithm, overgeneralize what they know and apply some number concepts to other examples, and/or have not fully grasped the concept in order to check if their answers make sense.
Children need many opportunities to talk about strategies for developing their number and operations concepts, as well as, fractions, and decimals.  They need to learn how to apply number sense, estimation, or place value to their calculations.  Teachers need to strive for conceptual understanding that connects the notation with the value that is being presented.  The use of manipulatives, such as craft sticks, rubber bands, connecting cubes, a hundreds chart, number lines, counters and a cup, base – ten blocks on centimeter grid paper, arrays should be used to tackle real – world problems facilitated by the teacher. Students can use concrete models or draw pictures by partitioning numbers and develop their own strategies or procedures that make sense to them.  Encountering many types of representations helps students focus on the similarities among models, which strengthens their understanding of key ideas. 

Common Misconceptions Students Have:
Misconception
Examples
Ideas for Instruction
Some count two objects when saying “sev-en” because of the double syllables in the word.
 
Students skip over some words while returning to words that were already recited. 
·       Read Number Books
·       Count out loud often
·       Counting songs and chants
·       Counting games

Video: Creative Ways to Teach Your Child How to Count at Home
Thinking Addition Means “Join Together” and Subtraction Means “Take Away” Often, students confuse the operations when the word more is used and sometimes think that take away  means to remove instead of finding the difference.
·       The teacher needs to ensure that they use the words plus and add, as well as,  minus and subtract when referring to subtraction symbol and reinforce this when students read their equations.
Renaming and Regrouping when Adding and Subtracting Two - Digit Numbers Due to students’ difficulty understanding place value, they are unable to compute correctly.
·       Counting and grouping objects by ones and tens.
·       Manipulatives
·       Hundreds Chart

Misapplying Addition and Subtraction Strategies to Multiplication and Division
 
Students confuse the commutative property of addition with the commutative property of multiplication.  When using estimation to multiply, students forget to compensate at the end.
·       Use the area model to help students see another representation of their multiplication expressions. 
Multiplying Two-Digit Factors by Two-Digit Factor
 
When multiplying two digit factors by two digit factors, students often forget to multiply by both digits. 
·       Model cross-product problems using arrays that illustrate the commutative and the distributive properties of multiplication. 
Understanding the Division Algorithm Teachers come up with creative ways to teach the division algorithm, focusing on the individual digits rather than the whole numeral. 
          Students are taught to ignore place value as they routinely work through a procedure they don’t necessarily understand.  
·       Ask students to share the strategies they used to get their answers and then discuss whether these answers make sense.
 
·        Divide by using Partial Products or
         "Friendly Numbers."

Understanding Fractions Children often struggle with the concepts of half and other equal fractional portions because of their prior experiences of sharing or dividing things unequally.
 
Students have difficulty dividing nontraditional shapes into parts such as thirds.
·       Explore the concept of fair shares.
·       Present a variety of shapes for students to divide so that students see that not all shapes are divided in the same way. 
·       Expose students to more than just haves, thirds, and fourths

Video: Fourth - graders investigate how to share 12 cookies amongst 8 people

 Video:  Understanding Fractions using Pattern Blocks
Adding and Subtracting Fractions Students treat each digit in a fraction as a whole number and add them separately. They are likely to add the numerators together and the denominators together.
·       Use the number line to represent fractions.
·       Use manipulatives, such as pattern blocks and fraction strips to count by fractions.

Video:  Using Fraction Strips to Add Fractions
 
Students have difficulty naming decimal fractions and are unable to provide the correct word form.
They may not be able to show the relation of a decimal expression to the whole.
Students have difficulty comparing decimals and ordering them.
·       Teachers need to name decimal fractions consistently and appropriately, thus reinforcing place value.
·       Use tools such as base –ten blocks, a meter stick, Digi-blocks, and money to effectively represent decimals.




    Effective teachers need to be aware of the confusion that students may face and provide engaging learning opportunities in order for children to succeed.  It is important for students to grasp the foundational knowledge and concept of the skill that is being taught before being introduced to a set of procedures provided by an algorithm that they may not fully understand. 

 
Questions to Ponder...

Should traditional algorithms be taught in the early elementary grades?


What are some common misconceptions your students have with number concepts?


How do you plan instruction to clear up any misconceptions that students have?








Here are some fun and interactive math games to help students practice their Basic Skills:

Addition
Subtraction
Multiplication
 
Division
Mixed Review
Fractions and Decimals
Bugabaloo:
 
Fruit Shoot
 
Penguin Party Addition
 
 
Addition Matching Game
 
Balloon Pop - Addition
 
 
Number Line Addition
 
Add Like Mad
 
 
Addition with missing numbers
 
Pac-Man Addition
 
Number Twins Addition
 
 
 
 
 
Kitten Match
 
 
Soccer Math: Adding 2 – Digit Numbers
 
Okta’s Rescue: Counting and Adding the number of Octapus’ rescued
 
 
 
 
 
Subtraction Harvest:
 
 
Fruit Shoot
 
Pearl Search
 
 
Subtraction Matching Game
 
Number Line Subtraction
 
Subtraction Action
 
Subtraction with Missing Numbers:
 
Pac - Man Subtraction
 
 
Stun attack
 
Multiplication Matching Game
 
Balloon Pop - Multiplication
 
 
Multiplication Station:
 
Multiplication with Missing Numbers:
 
Pac-Man Multiplication:
 
Shooting Fruits: Multiples
Pumpkin Multiples
 
 
 
Space Race
 
Grand Prix Multiplication
 
 
Penguin Jump Multiplication
 
Product Game: 2-players – Get Four in  a Row
http://illuminations.nctm.org/ActivityDetail.aspx?ID=29
 
 
 
 
 
Division Station:
 
Division with Missing Numbers
 
Pac-Man Division
 
Demolition Division
 
Drag Race Division
 
Division Derby
 
 
 
 
 
Interactive Hundreds chart
 
Math Lines
 
Monkey Drive
 
 
Catch the Falling Stars
 
 



Fruit Shoot: Number – Word Match


Fruit Shoot: Mixed Operation

 
Mixed Arithmetic/ Operations
 
Counting, Adding and Subtracting Bubbles under a Seashell
 
Make 24
 
Primary Krypto: Similar to Make 24, choose the operation (+,-,x,÷) to make the target number
 http://illuminations.nctm.org/ActivityDetail.aspx?ID=173
 
 
Select from a list of Counting games, adding games, Multiplication or Fraction Games
http://www.maths-games.org/

Timez Attack: As the player travels through the dungeon conquering monsters, they learn their basic facts in either multiplication, division, addition, or subtraction
http://www.bigbrainz.com/
 
 
 
Comparing Fractions
 
Haunted Comparing 3 Sets of Fractions Game http://www.mathplayground.com/HauntedFractions/HFGameLoader.html
 
Equivalent Fractions
 
 
Adding Fractions
 
 
 
 
 
Puppy Chase Decimals
 
Hungry Puppies Decimals
 
 
Puppy Pull
Decimal
 


   
Resources
Math Misconceptions: Pre K - Grade 5:  From Misunderstanding to Deep Understanding.  Bamberger, Honi J; Oberdorf, Christine; Schultz - Farrell, Karren.  Heinemann.  Portsmouth, NH 2010.

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