Topicmf6330c8ce821a73a_1528449000663_0Topic

Writing and reading algebraic expressions

Levelmf6330c8ce821a73a_1528449084556_0Level

Second

Core curriculummf6330c8ce821a73a_1528449076687_0Core curriculum

III. Creating algebraic expressions with one or more variables. The student:

1) writes down the results of a given operation in the form of algebraic expressions with one or more variables,

3) writes down the relations presented in the exercises, in the form of algebraic expressions with one or more variables,

4) writes down the solutions to the exercises in the form of algebraic expressions, like in the example below:
Bartek and Grześ were picking up chestnuts. Bartek collected n chestnuts and Grześ collected 7 times more. Then, on the way home, Grześ lost 10 chestnuts and gave half of the remaining ones to Bartek. How many chestnuts do Bartek and Grześ have now?

Timingmf6330c8ce821a73a_1528449068082_0Timing

45 minutes

General objectivemf6330c8ce821a73a_1528449523725_0General objective

Using mathematical objects, interpreting mathematical concepts.

Specific objectivesmf6330c8ce821a73a_1528449552113_0Specific objectives

1. Writing and reading algebraic expressions.

2. Writing down the content of an exercise in the form of algebraic expressions.

3. Communicating in English, developing basic mathematical, computer and scientific competences, developing learning skills.

Learning outcomesmf6330c8ce821a73a_1528450430307_0Learning outcomes

The student:

- writes and reads algebraic expressions,

- writes down the content of an exercise in the form of algebraic expressions.

Methodsmf6330c8ce821a73a_1528449534267_0Methods

1. Discussion.

2. Situational analysis.

Forms of workmf6330c8ce821a73a_1528449514617_0Forms of work

1. Individual work.

2. Group work.

Lesson stages

Introductionmf6330c8ce821a73a_1528450127855_0Introduction

The teacher informs the students that during this class they will learn what algebraic expressions are and how to write and read them.

Task

Using the internet resources, students look for the information about algebraic expressions: how they differ from arithmetic expressions and how algebraic expressions are called.

Proceduremf6330c8ce821a73a_1528446435040_0Procedure

Students share their information and write down the conclusions.

Algebraic expressions can contain letters, numbers and signs of mathematical operations as well as brackets. Letters occurring in algebraic expressions are called variables.
In algebraic expressions, we can omit the multiplication sign between two letters or a letter and a number, if the letter comes first.
The name of the algebraic expression is determined by the operation which, according to the order of operations, would be done as the last one.mf6330c8ce821a73a_1527752263647_0Algebraic expressions can contain letters, numbers and signs of mathematical operations as well as brackets. Letters occurring in algebraic expressions are called variables.
In algebraic expressions, we can omit the multiplication sign between two letters or a letter and a number, if the letter comes first.
The name of the algebraic expression is determined by the operation which, according to the order of operations, would be done as the last one.

Task

Using algebraic expressions, students write down the quantities below.

a) half of the number z,
b) the number smaller by 4 than r,
c) the product of the number w and the sum of numbers a and b,
d) the number greater by 45% than d.

Task

Students name the algebraic expressions below.

a) $3+ab$,

b) $(x-y{)}^2$,

c) $\frac{2d}{a+b}$,

d) $(3e+z)(s-t)$.

Task

Students work indvidually, using computers. Their task is to match the algebraic expression with the right verbal description.
Students write down the answers to the questions in the exercises, using algebraic expressions.mf6330c8ce821a73a_1527752256679_0Students work indvidually, using computers. Their task is to match the algebraic expression with the right verbal description.
Students write down the answers to the questions in the exercises, using algebraic expressions.

[Geogebra applet]

Task

Krzyś can put 30 cars in a big box and 12 cars in a small box. Krzyś has d big boxes and m small boxes.

a) How many cars will fit in both boxes?
b) How many cars will fit in both boxes, if Krzyś buys 2 more big boxes?
c) How many cars will fit in the boxes, if 3 little boxes get damaged?
d) How many cars will fit in the boxes, if Krzyś buys x big boxes and y small boxes?

An extra task:

X grams of water and s grams of salt were mixed. Students give the formula to determine the percentage concentration for the brine.

Lesson summarymf6330c8ce821a73a_1528450119332_0Lesson summary

Students do the revision exercises.

Then together they sum‑up the classes, by formulating the conclusions to memorise.

- Algebraic expressions can contain letters, numbers and signs of mathematical operations as well as brackets. Letters occurring in algebraic expressions are called variables.

- The name of the algebraic expression is determined by the operation which, according to the order of operations, would be done as the last one.

Selected words and expressions used in the lesson plan

algebraic expressionalgebraic expressionalgebraic expression

algebraic sumalgebraic sumalgebraic sum

algebraic productalgebraic productalgebraic product

algebraic quotientalgebraic quotientalgebraic quotient

variablevariablevariable