Mathematics / Year 7 / Algebra

Curriculum content descriptions

recognise and use variables to represent everyday formulas algebraically and substitute values into formulas to determine an unknown (AC9M7A01)

Elaborations
  • linking variables to attributes and measures being modelled when using formulas, such as the area of a rectangle is equal to the length x width as \(A\;=\;l\;\times\;w\) or using \(p\;=\;6g\;+\;b\) to describe a total of points expressed as goals (worth \(6\) points) and behinds (worth one point)
  • interpreting and using formulas obtained from other sources; for example, maximum heart rates and target heart rates for moderate exercise
  • substituting numerical values for variables when using formulas and calculating the value of an unknown in practical situations; for example, calculating weekly wage \(W\) given base wage \(b\) and overtime hours \(h\) at \(1.5\) times rate \(r\), \(W\;=\;b+1.5\times h\times r\), using values for mass \(m\) and volume \(v\) to determine density \(d\) of a substance where \(d\;=\;\frac mv\)
  • using everyday formulas and their application to contexts on Country/Place, investigating the relationships between variables
General capabilities
  • Critical and creative thinking Critical and Creative Thinking
  • Numeracy Numeracy
ScOT terms

Substitution,  Variables (Mathematics),  Equations

Video

Patterns, primes and Pascal's Triangle

Are you intrigued by patterns? Check out Vi Hart as she explains how to visualise patterns in prime numbers, using Ulam's Spiral. Watch as Vi creates patterns, using Pascal's Triangle to explore relationships in number. See what happens when she circles the odd numbers. What rule does she use to create the final pattern?

Video

MathXplosion, Ep 22: How to communicate numbers with Roman numerals

Explore an alternative way to communicate numbers using the anchor numbers 5 and 10 and the ancient Roman counting system based on letters. Roman numerals were used throughout Europe well into the middle ages and still appear in the names of monarchs, the production year of films, on buildings and on timepieces.

Video

Algebra basics video

Use this video as a springboard to introduce algebraic thinking, and to apply that thinking to a financial context, drawing on reasoning.

Video

MathXplosion, Ep 49: The probability of finding matching socks

Check out this probability puzzle that requires you to weigh all the possibilities. Pick the most likely outcome when confronted with a drawer full of loose, unpaired socks! How did Eric come up with a matching pair?

Video

Rounding decimals to the nearest tenth

This is a digital resource comprising a video demonstration of rounding a decimal fraction to the nearest tenth. The commentary uses and interchanges between the language of decimal places and decimal place values expressed in terms of tenths and hundredths. Practice questions dealing more broadly with rounding numbers ...

Video

Solving percentage problems

This digital resource is a video demonstration of a procedural method to calculate an unknown quantity, given an amount is a known percentage of the unknown. For a single example, students are presented with an algorithmic, step-by-step, pen-and-paper method. The demonstration is complemented by the presenter's commentary ...

Video

MathXplosion, Ep 50: How to use a tetrahedron to solve the tree problem

How can you place four trees exactly the same distance apart from one other? By making a model! By using miniature trees to make a model of the problem, it becomes clear that a 2D solution is impossible. We learn how objects can help us visualise the problem situation, which in this case requires a 3D solution: a tetrahedron.

Video

My Five Cents: Why investing can be risky

Planning to get rich quick by investing one day? Before you jump in, let Gen Fricker explain some of the risks involved with different types of investments. Then test yourself with ASIC MoneySmart's "Things to think about" classroom exercises.  

Video

MathXplosion, Ep 1: Magic 9s

Follow these simple calculations to illustrate the special properties of the number 9. Pick your favourite number between 1 and 9 and multiply that number by 3. Add 3 to your answer. Multiply the result by 3. Treat your two-digit answer as two separate numbers and add them together. No matter what number you pick to start ...

Video

Catalyst: Probability and the birthday paradox

Even when a maths problem seems simple – for example, the chance of two people sharing a birthday – the maths can run counter to our human intuition. Mathematician Lily Serna poses a maths problem to the Clovelly Bowling Club: how many people do you need to gather to get a 50 per cent chance of any two people in that group ...

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Catalyst: Small scale measurements

What units of measurements do we use to describe incredibly small things like blood cells and atoms? Watch as you are taken on a journey to explain the different units of measurement that we use to describe the very small.

Video

Working out the areas

Do you know how to work out the area of a square, a rectangle or a triangle? Learn the simple maths formulas needed from this video. What would be the area of a rectangle with a height of 5cm and a length of 3cm?

Video

The amazing 'angle-a-tron'

Lost your protractor? Well, find out how to make an 'angle-a-tron'. This might just be the coolest mathematical tool you've ever used. Measure all sorts of angles. It's easy with an angle-a-tron!

Video

MathXplosion, Ep 33: On the grid

Explore graphs, grids and mapping with a focus on reading and writing location data using coordinate geometry. Grids and maps illustrate the concepts of parallel/perpendicular lines (axes or labelled number lines), ordered pairs and intersection points.

Video

Comparing fuel consumption

Is it more fuel efficient to drive or fly between two places? Watch this clip and learn how to calculate the answer. What are the various factors that need to be taken into account? This video was made using the American measurement of gallons per hour, American firgures for the average number of passengers in a car and ...

Video

My Five Cents: What is opportunity cost?

What is the true cost of buying something? Gen Fricker explains that it's more than just money. Learn about opportunity cost - what it is, why it's a helpful tool and when to use it. Simple! Then test yourself with ASIC MoneySmart's "Things to think about" classroom exercises.  

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MathXplosion, Ep 8: Birthday probability

What is the probability there are at least two people in your class who have the same birthday? If you have at least 23 people in your class, the chances are good. Find out the maths behind this theory.

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MathXplosion, Ep 7: The power of exponents

Have you heard of the term "exponential growth"? Growth can occur very quickly when powers are involved. See how you can use the power of two to rapidly increase the amount of anything from grain to coins!

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MathXplosion, Ep 17: Develop mathematical mind-reading skills

Amaze your friends with your super mind-reading skills. Here’s a brain game you can play by asking a few questions and substituting letters for numbers! Learn to follow a specific sequence of arithmetical steps to always arrive at the same answer.

Video

Catalyst: Probability and the gambler's fallacy

Mathematician Lily Serna visits Luna Park to explain a great probability pitfall. She shares a century-old tale from Monte Carlo casino, and then she puts its lesson to the test. If you flip a coin and it lands on heads three times in a row, what result would you predict for the next flip? Find out why intuition might land ...