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The difference bar: generate hard subtractions

TLF ID L112

Learn how to split up numbers in your head. Use a linear partitioning tool to help find the difference between pairs of two-digit numbers such as 25 and 44. In most of these examples, the difference is greater than ten. Split the numbers into parts that are easy to work with, work out each part and then solve the original calculation. This learning object is one in a series of five objects.

Educational details

Key learning objectives
• Students use a linear model to solve differences mentally.
• Students partition numbers and investigate strategies to solve differences mentally.
• Students apply the associative principle to solve differences mentally.
Educational value
• Encourages students to solve subtractions using mental strategies.
• Provides a series of random two digit whole number pairs which students are challenged to find the difference between.
• Provides hints for mental strategies that aid student subtraction skills.
• Provides an option to print a worksheet for each completed equation, showing the student's working out.
Year level

3

Learning area
• mathematics
Strand
• Mathematics/Number and algebra
Concept
• Mathematics/Subtraction
• Mathematics/Counting strategies
• Mathematics/Number relationships
• Mathematics/Algorithms
• Mathematics/Mental arithmetic
• Mathematics/Number patterns
• Mathematics/Whole numbers
Skill
• Analysis;
• Application;
• Comprehension;
• Knowledge
Student activity
• Interactives;
• Analysis;
• Experiment;
• Modelling
Learning design
• Independent learning;
• Experiential learning;
• Problem solving;
• Visual learning

Other details

Contributors
• Technical implementer
• Subject matter expert
• Publisher
• Date of contribution: 20 Sep 2013
• Organisation: Education Services Australia
• Address: Melbourne VIC 3000 Australia
• URL: http://www.esa.edu.au/
Access profile
• Colour independence
• Device independence
• Hearing independence
Learning resource type
• Interactive Resource
Browsers
• Microsoft Internet Explorer - minimum version: 8.0 (MS-Windows) - maximum version: 9.0 (MS-Windows)
• Firefox - minimum version: (MS-Windows)
• Safari - minimum version: 5.1 (MacOS)
Operating systems
• MacOS - minimum version: 10.6
• MS-Windows - minimum version: XP - maximum version: 7
Rights
• © Education Services Australia Ltd, 2013, except where indicated under Acknowledgements.