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Listed under:  Mathematics  >  Number (Mathematics)  >  Number operations  >  Subtraction
Online

reSolve: Algebra: Odds and Evens

This sequence of two lessons focuses on developing students' understanding of the properties of odd and even numbers. Students explore the results of adding and subtracting odd and even numbers and use these results to make generalisations. They then apply this generalisation to solve problems and to explore patterns. The ...

Online

reSolve: Algebra: Chess - The King

This lesson aims to build students' algebraic reasoning and understanding of number as they explore computation on the number chart. Students explore the moves of a king chess piece and how the value of the numbers change as he moves. This builds into an algebraic exploration of equivalent values that can be found on the ...

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 ...

Interactive

Fraction fiddle: hit the apple

Help an archer to hit an apple with his arrow. Build two fractions to make a total of one whole. Complete the numerators of both fractions (they may have fixed denominators). For example, work out how many quarters and how many eighths can be added together to total one whole. Look at fraction bars and a number line to ...

Video

Subtracting decimals

This is a video demonstration, with audio commentary, of the procedure for pen-and-paper subtraction of decimal fractions. In the commentary, the presenter emphasises the links with the underpinning concepts of place value. Practice questions, limited to subtraction of decimal fractions involving tenths and hundredths, ...

Online

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 ...

Online

reSolve: Addition: Partitioning

This sequence of two lessons explores early algebraic thinking around the concept of equivalence. Students develop equivalence understanding by partitioning numbers into two parts. They explore the commutative property and compensation as they are challenged to find all possible combinations. Each lesson is outlined in ...

Online

reSolve: Lamingtons

This sequence of three lessons explores the mathematical idea that fractions represent division. In the first lesson, students are invited to solve a problem involving fair sharing of different plates of lamingtons. Students explore how the denominator represents how many shares and the numerator represents the number being ...

Interactive

Equivalent linear algebraic expressions

This is a six-page HTML resource about solving problems concerning equivalence of linear algebraic expressions. It contains one video and four questions, three of which are interactive. The resource discusses and explains equivalence of linear algebraic expressions to reinforce students' understanding.

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. ...

Online

reSolve: Algebra: Triangle Inequality

This sequence of two lessons explores the triangle inequality theorem. Students are challenged to construct triangles with a given number of matchsticks, explore and record what combinations of sticks can create valid triangles and represent their findings using mathematical expressions. Each lesson is outlined in detail ...

Online

reSolve: Algebra - Equivalence

This sequence of two lessons builds students' understanding of equivalence as balance. The equals sign is used to indicate the same value on both sides of an equation. Students develop their understanding of equivalence by looking at balancing scales with blocks of different weights. Each lesson is outlined in detail including ...

Online

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 ...

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

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

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

Wishball: hundreds

Test your understanding of place value with three-digit numbers. Start with a three-digit whole number such as 507. A spinner provides a randomly generated digit. Choose its place value and add it to (or subtract it from) your starting number. Work towards a given target number, say 539, using other digits. You can choose ...

Video

Count Us In, Ep 8: How many are left?

Flynn and Dodly are practising their magic tricks. They are trying to make eggs, muffins and even guinea pigs disappear. Help our two friendly monsters work out how many should be left after their disappearing tricks.

Video

Musical fractions

Break down a song by counting how long the notes are in action! Learn about patterns in rhythms and musical notes, and discover the role of fractions in denoting whole, half and quarter notes and creating distinct sounds.