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Listed under:  Mathematics  >  Number (Mathematics)  >  Number operations  >  Mental arithmetic
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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.

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MathXplosion, Ep 11: Fun facts about the number seven

Did you know that the digits on opposite faces of dice will always add up to seven? Use dice as fun tools to reinforce fact families of seven, multiples of seven and subtraction skills.

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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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reSolve: Multiplication - The Tiler

This task explores arrays through the context of a tiling a courtyard. Students are given the total cost of tiling a courtyard and use this to calculate the price for individual tiles. They then explore the cost of different tiling designs to determine if one is cheaper than another. Each lesson is outlined in detail including ...

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reSolve: Authentic Problems: 10000 Centicubes

This sequence of four lessons integrates content in number and measurement to deepen students' understanding and confidence working with larger numbers. Students work flexibly with numbers up to 10 000 as they determine suitable dimensions for a container that can hold 10 000 centicubes. They are challenged to plan, construct ...

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reSolve: Authentic Problems: What's For Lunch?

This sequence of four lessons invites students to investigate how many of a chosen food item are eaten at their school in a year. Students identify the mathematical knowledge they need to find how many of the selected items they eat in a year and devise a plan to find the total number, using grouping, partitioning and repeated ...

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reSolve: Measurement - Jump!

In this sequence of two lessons, students investigate how far they can jump and explore the jumping distance of a range of animals. Students first estimate the distance they can jump, then undertake an investigation by jumping using a range of techniques. Class data is recorded and displayed and students compare their jumping ...

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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 ...

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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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reSolve: Algebra: Number Sequences

This sequence of lessons aims to build students' algebraic thinking through explorations of additive number patterns. Students are challenged to solve problems to generate patterns, explore strategies for addition and subtraction and apply their skills to constructing their own new patterns.The lessons are outlined in detail ...

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reSolve: Area and Perimeter

This series of three lessons explores the relationship between area and perimeter using the context of bumper cars at an amusement park. Students design a rectangular floor plan with the largest possible area with a given perimeter. They then explore the perimeter of a bumper car ride that has a set floor area and investigate ...

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MoneySmart: The house of needs and wants

This is a unit of work integrating aspects of the mathematics, English and science curriculums around planning a school breakfast. The unit was written for year 3 and is intended to take about 12 hours. It consists of 11 student activities supported by teacher notes on curriculum, pedagogy and assessment. Student activities ...

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MathXplosion, Ep 31: Heavy vs big

How would you measure and compare the weight of something? Learn why big things aren't necessarily heavy. All you need is something heavy and a lot of something light and you’ll be able to prove that weight is not the same as size.

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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, ...

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reSolve: Multiplication - Domino Arrays

This sequence of two lessons explores multiplicative thinking through the use of arrays where all the parts of the array are not visible. The sequence encourages students to find the total number of items in an array by multiplication rather than counting by ones or skip counting. Connections between area, arrays and multiplication ...

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MathXplosion, Ep 40: Kaprekar's operation

Did you know that 6,174 is a very mysterious number? In 1949, the mathematician Dr Kaprekar from India devised a process now known as Kaprekar's operation. First, choose a four-digit number where the digits are all different. Then rearrange the digits to get the largest and smallest numbers these digits can make. Finally, ...

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Introduction to binary

This sequence of lessons focuses on what a binary number is, what a decimal number is, why binary numbers are important in digital systems and how to read and understand a binary number.

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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 ...

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reSolve: Multiplication - reSolve Bakery

This series of three lessons explores strategies for multi-digit multiplication. Students are presented with a range of problems in the context of a bakery producing arrays of cupcakes. The lessons aim to develop a range of strategies based on the associative and distributive properties of multiplication, moving students ...

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Mental computation

This is a website designed for both teachers and students that discusses methods of mental computation. In particular, applying the associative, commutative and distributive laws to aid mental and written computation is discussed. These are important ideas for the introduction of algebra. There are pages for both teachers ...