# Inequality symbols and relationships

*Keywords:*

AO elaboration and other teaching resources

AO elaboration and other teaching resources

The purpose of this unit of three lessons is to develop understanding of how to recognise and record relationships of (equality and) inequality in mathematical situations.

- Understand the equals symbol as an expression of a relationship of equivalence, and explain this.
- Recognise situations of inequality and use the inequality (‘is not equal to’) symbol, ≠.
- Understand that < and > symbols can make equivalent statements.
- Use relationship symbols =, <, > in equations and expressions to represent situations in story problems.
- Understand how to find and express the difference between unequal amounts.

The first relationship symbol that most students encounter is the equals symbol, =, which communicates a relationship of equivalence between amounts. It is important for students to understand that symbols help us to express relationships between numbers and that equivalence is just one such relationship.

Inequality is the relationship that holds between two values when they are different. Their relative value is described with specific language including ‘is greater than’, ‘is more than’, ‘is bigger than’ or ‘is less than ‘ or ‘is fewer than’. These are expressed using the symbols, <, >, which are said to show ‘strict’ relationships of inequality. Whilst not introduced here, the symbols, ≤ , meaning ‘is less than or equal to’, and , ≥, meaning ‘is greater than or equal to’, are known as ‘not strict’. The notation ≠, meaning ‘is not equal to’ is briefly introduced here as it is a useful, if infrequently used, relationship symbol.

Algebra is the area of mathematics that uses letters and **symbols** to represent numbers, points and other objects, as well as **the relationships between** them. Through exploring both equality and inequality relationships, and the symbols used to express these, students develop an important and heightened awareness of the *relational* aspect of mathematics, rather than simply holding the computational view of mathematics that arises from the arithmetic emphasis that is dominant in many classrooms.

The activities suggested in this series of lessons can form the basis of independent practice tasks.

**Links to the Number Framework **

Counting all (Stages 2 and 3)

Advanced counting (Stage 4)

Early additive (Stage 5)

The activities suggested in this series of lessons can form the basis of independent practice tasks.

**Session 1**

SLOs:

- Understand the equals symbol as an expression of a relationship of equivalence, and explain this.
- Recognise situations of inequality and use the ‘is not equal to’ symbol.
- Recognise and describe in words the relative size of amounts.

__Activity 1__

- Begin by talking about buildings in your school, suburb, town, city, or a city nearby. List any tall buildings which are known by name. Ask if anyone knows any (familiar) buildings that might be the same height.
- Show a skyline picture such as this and ask what features the students notice. (eg. ‘buildings are of different heights’.)

Elicit descriptive, comparative language: tall, taller, tallest, short, shorter, shortest, same).

Point out that we have been comparing and describing the buildings*in relation to one another*. Explain we will be investigating*relationships*between numbers. - Make unifix cubes available to the students, and tell them to think of their favourite number between (and including) one and ten. Ask them to take this number of cubes of
**one colour**.

For example, one student takes seven pink cubes.

Place a simple city street map in front of the students, or create one with them.

Have the students join their cubes to make buildings for this city. When they made their ‘tower buildings’, have them locate them, standing up, in places of their choice between the streets, creating a ‘cityscape.’ - Have students look carefully at their ‘city’ and identify any buildings that they think might be the same height. Select several students to test their idea by taking the two identified ‘towers’, standing them side-by-side and comparing their heights. If they are the same they should count the number of ‘storeys high’ they are (number of cubes) and, on the class chart, write an equation and words to show this. For example:

5 = 5 five is equal to five

Read the equation together, “Five is equal to five” and “Five is the same as five.”

The buildings are then returned to their place ‘in the city’. - Have students now identify towers that are not the same in height.

Have a student describe how these numbers (of storeys) are ‘related’: “seven is more than five”, “five is less than seven”,*“seven is not equal to five.”*Ask, “How can you write this?” Record the students’ suggestions, accepting all ideas.

On the class chart write, and have students in pairs, read this (expression of inequality)to each other. Read this together.**7 ≠ 5 seven is not equal to five** - Have students identify more ‘unequal buildings’ and record these as inequality statements on the chart and read them.

If possible retain the class ‘cityscape’ for Session 2.

__Activity 2__

Make plain A4 paper, felt pens, and cubes available to students. Have them work in pairs to create their own small ‘city’ (with street map and cube buildings). On separate paper, **each** student is to write about the buildings in their ‘city’. They should **draw** at least four pairs of buildings and for these, write both **equality** and **inequality** statements in **words** and **symbols**, as modelled in Activity 1, Step 5 (above).

Have student pairs retain their maps for Session 2.

__Activity 3__

Conclude the session by sharing their recording and discussing how the symbols = and ≠ show us **how numbers are related** to each other.*Suggestion: Photograph class and pair ‘city models’ to display with student recording from 2. (above), and from further sessions.*

**Session 2**

SLOs:

- Recognise situations of inequality and use the appropriate symbols, ≠, <, >, to express this.
- Understand that in using < and > symbols, we can make equivalent statements.

__Activity 1__

- Place the class ‘city’ from Session 1, with its map and tower buildings, in front of the students. Review the symbols = and ≠ and ask the students, “What is common about these symbols?” (They both express a relationship between numbers.)

Explain that there are more*relationship symbols*, and that they will learn about two more in this session. - Ask for a volunteer to find two towers that match this number expression:

6 ≠ 4

Have student pairs discuss the towers,

then, as a class, record their observations, including ‘6 is more than 4’ and ‘4 is less than 6.’ Ask if anyone knows**symbols**that show each of these relationships. - Write these symbols on the class chart.
**< >**

Write the words, ‘*is more than*’, and ‘*is greater than*’, together on the class chart, and ‘*is less than*’ or ‘*is fewer than*’ together.

Have students discuss these in pairs and decide**which symbol goes with which pair of phrases**and**why**they think that. - Accept all ideas. Conclude, agree, model and record:
**6 > 4**

six is greater than/is more than 4

__Activity 2__

- Make available to the students small pieces of card (the same size)and felt pens or pencils. Explain that they are now to work in pairs with their own ‘city’.

Each student is to write at least four inequality cards for pairs of ‘buildings’. For example: - Have the students then
*mix up their cards so that they*, swap with another student pair, and correctly match their cards and ‘buildings’.*don’t match the ‘buildings’*

__Activity 3__

- As a class, now discuss and conclude that the same relationships can also be expressed using the “is less than’ or ‘is fewer than’ symbol. Demonstrate with ‘buildings’ (cubes) from Activity 1, Step 4. (above):
**four is less than/is fewer than 6** - Have students return to their own displays from 2.i. (above) and write four more cards expressing ‘is less than’ relationships’.

Each student should now have written at least 4 pairs of cards, 16 cards in total for the pair.

__Activity 4__

- Have students shuffle the cards they have made in Activity 3, Step 2 (above) and swap these with another student pair.

Each pair should play a shortgame with these cards by spreading them out, face down in front of them, trying to find matching pairs of statements, for example:**Memory** - Students who finish quickly can create towers to match some of the pairs of inequality statements.

__Activity 5__

Conclude the session by reviewing the four relationship symbols, one of equality and three of inequality, that have been used in Sessions 1 and 2.

=, ≠, <, >.

Retain student ‘cities’ and relationship cards for Session 3.

**Session 3**

SLOs:

- Use relationship symbols =, <, > in equations and expressions to represent situations in story problems.
- Understand how to find and express the difference between unequal amounts.

__Activity 1__

- Begin asking, “Who walked to school this morning?” Say that you are going to read a short story (Attachment 1).

Explain that the students must listen very carefully to the story. As they do so, they should record relationship expressions, in order, for any numbers that they hear. Read the story once. Highlight an example (eg. 3 >2 weetbix) and read the story again. - Have students compare their expressions and equation in pairs. Share and discuss these as a class, recording them on the class chart.

__Activity 2__

- Write the word
**‘difference’**on the class chart. Ask students to explain this, giving examples from their own life, and record their ideas. (for example: ‘There’s a difference between the number of people in my family and in Maia’s family. There’s five in my family and eight in Maia’s. They’re not the same.’) - Refer to the inequality expressions recorded on the class chart in Activity 1, Step 2 (above).

For each discuss and record the difference. For example:

Weetbix: 3 > 2, 2 < 3,

Three is**one**more than two. Two is**one**less than three.

The difference is**one**.

Age: 60 > 50, 50 < 60

Sixty is**ten**more than fifty. Fifty is**ten**less than sixty.

The difference is**ten**.

Cats: 6 > 0, 0 < 6

Six is**six**more than zero. Zero is**six**less than six.

The difference is**six**.

Dog: 1 = 1

One is the same as one. There is**no**difference.

The difference is**zero**.

__Activity 3__

- Make available to the students, small pieces of card (the same size) and felt pens or pencils.

Display two ‘towers’ from the class ‘city’. Ask. “What is the**difference**between the two towers?**How do you know?**” For example:

Show: and write

Elicit explanations such as: there are two more blue ones, there are two less/fewer green ones.

Write**6 – 4 = 2**on the class chart and on a card.

Highlight the fact that**when we solve a subtraction problem, we are***finding the difference*. - Have student pairs go to their ‘cities’ and relationship cards from Session 2.

Explain that they are to write a**difference card**, and a**subtraction equation card**as shown in Activity 3, Step 1 for each of their inequality expression pairs. Have partners check each other’s cards.

For the pair, there are now**32**cards in total,**8 sets of four cards**.

These can be put together in a bag, or combined with an elastic band. - Have student pairs exchange full sets of cards. Have pairs, or fours, play
with one set of cards.**Fish for Four**

(Purpose: To recognise equivalent pairs of inequality expressions, and their matching subtraction equation and difference statements)

How to play:

Cards are shuffled. Five are dealt to each player. The spare cards are put in a pile, face down, handy to all players.

Players check to see if they have any complete sets in their hand. If so, these are displayed face up in front of them. Each player then privately identifies which set they will collect and they take turns to ask one other named player for a specific card to complete their set.

For example:

In hand: and

At their turn, the player says, “ Name, do you have the card, four is less than six?”

If the named player has the card, they must forfeit it. The successful player can ask again till they are told, “No. Go fish.” That player then takes a card from the top of the upturned pile of spare cards. It is then the turn of the next player.

The winner is the player with the most complete sets when all cards are used.

__Activity 4__

Conclude this session by reviewing key learning from this series of three lessons. Cities can be dismantled. Sets of cards can be used as an independent consolidation task.

Dear Parents and Whānau,

In maths we mostly write equations. These use the =, equals, symbol. This symbol tells us that two amounts are equivalent. But sometimes numbers or amounts are **not equal**.

In maths this week, the students have been learning how to record **inequality** expressions such as 8 > 6, (eight is greater than or more than six) and 6 < 8 (six is less than or fewer than eight.) They have also learned to find the difference between numbers by solving a subtraction equation (in this case 8 – 6 = 2) and to state the difference (the difference is 2).

They have made their own card games to play with you at home.

Your child will explain how to play, ** Fish for Four**.

We hope you enjoy playing * Fish for Four*, and enjoy helping your child to practice their learning about inequality expressions and number relationships.

Thank you.

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InequalitySymbolsAndRelationshipscm1.pdf | 31.44 KB |