Mathematics / Year 4 / Algebra

Curriculum content descriptions

find unknown values in numerical equations involving addition and subtraction, using the properties of numbers and operations (AC9M4A01)

Elaborations
  • demonstrating the commutative properties of addition using materials, diagrams and number lines; for example, using number lines to demonstrate that \(5 + 2 = 2 + 5\), demonstrating that \(2 + 2 + 3 = 7\) and \(2 + 3 + 2 = 7\) and \(3 + 2 + 2 = 7\)
  • using balance scales and informal uniform units to create addition or subtraction number sentences showing equivalence, such as \(7 + 8 = 6 + 9\), and to find unknowns in equivalent number sentences, such as \(6 + 8 = \square + 10\)
  • using relational thinking and knowledge of equivalent number sentences to explain whether equations involving addition or subtraction are true; for example, explaining that \(27 \space– \space 14 = 17\space – \space4\) is true and using a number line to show the common difference is \(13\)
  • using part-part-whole diagrams or bar models to recognise and explain the inverse relationship between addition and subtraction, using this to make calculations easier; for example, solving \(27 + \square = 63\) using subtraction, \(\square = 63\space – \space27\)
General capabilities
  • Critical and creative thinking Critical and Creative Thinking
  • Numeracy Numeracy
ScOT terms

Associativity,  Mathematical expressions,  Subtraction,  Addition

Interactive

Sites2See: Patterns and Algebra

Selected links to a range of interactive online resources for the study of patterns and algebra in Foundation to Year 6 Mathematics.

Interactive

Wishball: whole numbers

Test your understanding of decimal place value with whole numbers. Receive a starting number, such as 3786, and work towards turning it into a target number, such as 7664. Spin a random digit, choose its decimal place value and decide whether to add or subtract the random digit from your starting number. You can use a 'Wishball' ...

Interactive

The difference bar: go figure

This tutorial is suitable for use with a screen reader. It explains how to split up numbers in your head when finding the difference between two numbers such as 26 and 73. Work through sample questions and instructions explaining how to use linear partitioning techniques. Find the difference between pairs of numbers. Split ...

Interactive

Circus towers: square stacks

Work out how many acrobats are needed to form square-shaped human towers. Start by building a square tower with four acrobats: two acrobats in the base layer and two acrobats standing on their shoulders. Examine a table and graph of the total number of acrobats in the towers. Predict the number of acrobats needed to build ...

Interactive

The multiplier: go figure

This tutorial is suitable for use with a screen reader. It explains strategies for solving complex multiplications in your head such as 22x38. Work through sample questions and instructions explaining how to use partitioning techniques. Solve multiplications by breaking them up into parts that are easy to work with, use ...

Interactive

Divide it up: puppies

Use a dividing tool to make equal shares of biscuits and toys in a pet shop. For example, share 34 biscuits equally between 6 puppies. Predict how many items each puppy will get, or how many packets can be filled. Check your prediction. Decide what to do with any leftovers. Complete a sentence describing the number operations.

Interactive

Wishball: hundredths

Test your understanding of decimal place value with numbers that include hundredths. Receive a starting number, such as 46.87, and work towards turning it into a target number, such as 85.32. Spin a random digit, choose its decimal place value and decide whether to add or subtract the random digit from your starting number. ...

Interactive

Wishball challenge: whole numbers

Test your understanding of decimal place value with whole numbers. Receive a starting number, such as 3786, and work towards turning it into a target number, 7664. Spin a random digit, choose its decimal place value and use the given operation (either addition or subtraction) on your starting number. Be careful not to overshoot ...

Interactive

The take-away bar: go figure

This tutorial is suitable for use with a screen reader. It explains strategies for solving subtractions in your head such as 87-39. Work through sample questions and instructions explaining how to use linear partitioning techniques. Solve subtractions by breaking them up into parts that are easy to work with, work out each ...

Interactive

Sushi monster - iTunes app

The Sushi monster needs to be fed the correct sum or product. Choose to play the addition or multipliaction game. In the addition game select the two numbers that make the target sum. In the multipication game select two numbers to make the target product. This game has several levels. Free when reviewed on 12/5/2015.

Interactive

Summing Decimals

An interactive resource in which students learn how to add and subtract numbers that have up to two decimal places.

Interactive

MoneySmart: helping out

This is an activity about making choices to raise money for imaginary animals called gumbutangs. Their habitat is being eradicated and something must be done to save them. The user's first choice is between two websites, one a trusted one, the other a scam site. Then they are given choices about how to raise money for the ...