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Learning objects Balance the blobs: find the rule 2

TLF ID L5980

Balance scales by using blobs. Using non-unit ratios, such as 3:2, 4:5 or 5:2, explore how many black blobs and white blobs balance each other. Discover the rule that balances the scales with the correct number and type of blobs. For example, 3 black blobs balance 2 white blobs. Find out how many black blobs balance 4 white blobs. Build a number pattern. Then use the rule to solve a problem by moving blobs to make the scales balance. Go on to balancing scales with black, white and grey blobs. This learning object is the second in a series of three learning objects.

Educational details

Key learning objectives
  • Students identify the numerical relationship (ratio) between two types of items.
  • Students investigate multiplication number sentences to record the equivalent relations.
Educational value
  • Introduces the concept of ratio with non-unit ratios such as 3:2.
  • Provides experience in basic algebraic thinking by moving from one-to-one correspondence thinking to one-to-many thinking.
  • Features a dynamic model of equality that allows the students to explore number relations through the equal-arm balance (scales).
  • Includes a printable worksheet for students with a record of the rule and its solution, and a new problem to solve using the same rule.
Year level

5; 6

Learning area
  • mathematics
  • Mathematics/Number and algebra
    • Mathematics/Algebra
    • Mathematics/Algebraic methods
    • Mathematics/Arithmetic
    • Mathematics/Equations
    • Mathematics/Number concepts
    • Mathematics/Number operations
    • Mathematics/Number patterns
    • Mathematics/Number relationships
    • Mathematics/Number sentences
    • Mathematics/Numbers
    • Mathematics/Thinking
    • Mathematics/Simple equations
    • Mathematics/Reasoning
    • Mathematics/Working mathematically
    • Knowledge;
    • Comprehension;
    • Application;
    • Analysis
    Student activity
    • Interactives;
    • Experiment;
    • Analysis;
    • Modelling
    Learning design
    • Experiential learning;
    • Independent learning;
    • Problem solving;
    • Visual learning

    Other details

    • Publisher
    • Date of contribution: 20 Sep 2013
    • Organisation: Education Services Australia
    • Address: Melbourne VIC 3000 Australia
    • URL:
    • Subject matter expert
    • Name: Dr Jenni Way
    • Organisation: University of Western Sydney
    • Address: Penrith NSW 2750 Australia
    • Script writer
    • Organisation: CADRE Design
    • Address: Ultimo NSW 2007 Australia
    • Technical implementer
    • Organisation: CADRE Design
    • Address: Ultimo NSW 2007
    • Educational validator
    • Name: Graham Jones
    • Organisation: Griffith University
    • Address: Broadbeach Qld 4218 Australia
    Access profile
    • Colour independence
    • Device independence
    • Generic
    Learning resource type
    • Interactive Resource
    • 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
    • © Education Services Australia Ltd, 2013, except where indicated under Acknowledgements.