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Listed under:  Mathematics  >  Number (Mathematics)  >  Number operations  >  Associativity
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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.

Online

Home energy use

Reducing carbon dioxide emissions and sustainable energy use and are two of the major issues facing the world today. This project explores energy use in homes, and compares individual energy use with the class average and calculate and graph CO2 emissions.

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Next Domino

This resource is a web page containing a short task to explore counting patterns. Dominoes are used to make counting patterns, add the next two dominoes that follow the pattern. A printable resource is also available to support the task. This resource is an activity from the NRICH website.

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Investigating the Dilution Series

This resource is a web page containing a short task to explore counting patterns. Dominoes are used to make counting patterns, add the next two dominoes that follow the pattern. A printable resource is also available to support the task. This resource is an activity from the NRICH website.

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

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 ...

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Chinese abacus, c1900

This is a rectangular wooden abacus (15.5 cm x 29 cm x 2.5 cm), made in about 1900. It has two decks (divided horizontally by the beam) of 13 rods inserted vertically in the frame. On the bottom deck there are five wooden beads on each rod and on the top deck there are two beads on each rod. The abacus has a removable wooden ...

Interactive

Wishball challenge: hundreds

Challenge your understanding of place value in whole numbers up to 999. Receive a starting number, such as 328, and work towards turning it into a target number, such as 177, within 20 turns. Spin a random digit, choose its decimal place value and use the given operation (either addition or subtraction) on your starting ...

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 ...

Online

reSolve: Multiplication - Cartesian Product

This sequence of two lessons introduces the idea of multiplication as a Cartesian product, using the language of 'for each'. Students learn to use a tree diagram to find the number of possible combinations that can be made in an animal mix and match book. They learn how a simpler problem can be used to help solve a larger, ...

Online

reSolve: Addition: Chess - The Rook

This lesson engages students in investigating place value and the addition and subtraction of numbers by exploring computation on the number chart. Students analyse the moves of a rook chess piece and how the value of the numbers change as he moves. This builds into an exploration of how the number chart can be used as ...

Online

reSolve: Counting Large Collections

This lesson engages students in investigating how to count a large number of objects. Students are encouraged to think of efficient counting strategies and effective ways to keep track of their count. They explore unitising, leading to an opportunity to explore the patterns formed and build an understanding of place value. ...

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

The difference bar: generate easy subtractions

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 34. In these examples, the difference is always less than ten. Split the numbers into parts that are easy to work with, work out each part and then solve the original calculation.

Interactive

Wishball challenge: tens

Challenge your understanding of place value in whole numbers up to 99. Receive a starting number, such as 86, and work towards turning it into a target number, such as 18, within 20 turns. Spin a random digit, choose its decimal place value and use the given operation (either addition or subtraction) on your starting number. ...

Video

MathXplosion, Ep 32: A mean trick

Learn a cool trick using the concept of the mean (or average). Pick any 3 x 3 block of dates on a monthly calendar. The number in the middle square is the mean of the nine numbers that form the 3 x 3 square. If you add all the numbers and divide the total by nine (the number of squares), the answer is the number in the ...

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Mixed Up Maths, Ep 1: Monumental measurement mess ups

Did you know that in Australia we use a metric system for measurement? See if you know the units of measurement for length, mass and volume. Find out what system the United States uses. You guessed it - they don't use the metric system! See how a mix up of these units can cause all kinds of mess ups.

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Tray Bake

This resource is a web page containing a short task to explore counting patterns. Dominoes are used to make counting patterns, add the next two dominoes that follow the pattern. A printable resource is also available to support the task. This resource is an activity from the NRICH website.

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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 ...