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Algorithms

A Flow Chart

What is it?

An algorithm is a series of ordered steps that are required to solve a problem. In order to work, algorithms need to have their steps in the right order.

Algorithms are everywhere in our daily lives. At their simplest level, algorithms exist as a series of instructions that enable us to solve simple problems; for example, recipes or getting ready for the day. Algorithms can also be more complex. For example, some of the largest corporations use algorithms to guide our internet browsing, airports use them to program flight paths and the health sector uses them to find donor–patient matches.

Australian Curriculum definition

Algorithms

Step-by-step procedures required to solve a problem. For example, to find the largest number in a list of positive numbers:

  • Note the first number as the largest.
  • Look through the remaining numbers, in turn, and if a number is larger than the number found in 1, note it as the largest.
  • Repeat this process until complete. The last noted number is the largest in the list.

An algorithm may be described in many ways. Flowcharts are often useful in visualising an algorithm.

Source: Australian Curriculum: Technologies glossary

RESOURCES

Learn more about it

What are algorithms?

This 5-minute video explores the making of a Vegemite sandwich and other processes to explain algorithms.

Problem-solving using algorithms

This 6-minute video explores some of the criteria and complexities of creating an algorithm that solves problems efficiently.

LESSON IDEAS

How to teach it

Primary

Introducing Algorithms

Introducing algorithms

Students design a sequence of steps for others to follow. They convey their instructions to peers and evaluate the work of others to determine if the outcome was successful.

Secondary

Getting warmer

Getting warmer

This lesson sequence intentionally uses a visual based programming tool to introduce designing and validating algorithms. Those students who complete this task can move to code the result in any text-based language with which they are familiar.


Eco Calculator

Eco calculator

Students make a paper prototype of an eco-calculator to demonstrate human impact on the environment and suggest changes in behaviour. This is an unplugged learning sequence with opportunities to extend learning through the development of a Scratch quiz.

Fibonacci Served Three Ways

Fibonacci served three ways

Students learn to code separate modules that perform discrete functions but collectively meet the needs of the solution. They select the most appropriate algorithm based on the type of problem.

Math Quiz

Making maths quizzes 1: Plan and test our programs

In this sequence students plan, create and edit a program that asks maths questions that are harder or easier depending on user performance.

There Can Only Be One

There can only be one

Students write a simple suite of programs that can be used to facilitate an SRC election though the collection and processing of data. It assumes that students have been introduced to Python programming language.

Math Quiz

Making maths quizzes 2: Implementing a digital solution

In this sequence students implement a digital solution for a maths quiz. They test and assess how well it works.

Breaking up can be good

Breaking up can be good

This sequence provides a gentle introduction to the skill of decomposition by having students develop discrete modules that together serve a single need: a maths teacher asks for a program that can be used to demonstrate aspects of maths. This sequence can be used in conjunction with 'Comparing and selecting appropriate algorithms'.

Planting Fruit And Vegetables

Planting fruit and vegetables

This sequence integrates science as students grow a plant from seed, capture each step and decision as an algorithmic process and record data for future learning.

Behaving With Real Class

Behaving with real class

One challenge in teaching object-oriented principles is finding a suitable programming language. Many of these languages are too complex and their environments too confusing. This lesson sequence offers a choice of one of two approaches in an attempt to address this problem.

Bee Bot

Buzzing with Bee-Bots

Students follow and describe a series of steps to program a floor robot. Plan a route to program a robot to follow a path and write a sequence of steps (algorithm).

Who wants to be a millionaire

Who wants to be a millionaire?

Drawing on the well-known wheat/rice and chessboard problem, students use spreadsheets to simulate iteration and to solve problems.

CURRICULUM LINKS

Levels F - 2

Follow, describe and represent a sequence of steps and decisions (algorithms) needed to solve simple problems (ACTDIP004)

Levels 3 - 4

Define simple problems, and describe and follow a sequence of steps and decisions (algorithms) needed to solve them (ACTDIP010)

Implement simple digital solutions as visual programs with algorithms involving branching (decisions) and user input (ACTDIP011)

Levels 5 - 6

Design, modify and follow simple algorithms involving sequences of steps, branching, and iteration (repetition) (ACTDIP019)

Levels 7 - 8

Design algorithms represented diagrammatically and in English, and trace algorithms to predict output for a given input and to identify errors (ACTDIP029)

Levels 9 - 10

Design algorithms represented diagrammatically and in structured English and validate algorithms and programs through tracing and test cases (ACTDIP040)

Implement modular programs, applying selected algorithms and data structures including using an object-oriented programming language (ACTDIP041)