Topicm62e30e88a152e0e6_1528449000663_0Topic

The order of operationsorder of operationsorder of operations

Levelm62e30e88a152e0e6_1528449084556_0Level

Second

Core curriculumm62e30e88a152e0e6_1528449076687_0Core curriculum

V. Calculations on common and decimal fractions. The student:

7) calculates values of simple arithmetic expressionarithmetic expressionarithmetic expression, applying rules about the order of operationsorder of operationsorder of operations;

9) calculates values of arithmetic expressionarithmetic expressionarithmetic expression that require arithmetic calculations on integers or numbers written as common fractions, mixed numbers and decimal fractions, also rational negative, not more difficult than: $-\frac{1}{2}:0,25+5,25:0,5-7\frac{1}{2}\cdot (2,5-3\frac{2}{3})+1,25$.

Timingm62e30e88a152e0e6_1528449068082_0Timing

45 minutes

General objectivem62e30e88a152e0e6_1528449523725_0General objective

Reading and interpreting data presented in various forms and processing it.

Specific objectivesm62e30e88a152e0e6_1528449552113_0Specific objectives

1. Calculating values of arithmetic expressions.

2. Applying rules about the order of operationsorder of operationsorder of operations.

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

Learning outcomesm62e30e88a152e0e6_1528450430307_0Learning outcomes

The strudent:

- calculates values of arithmetic expressions,

- applies rules about the order of operationsorder of operationsorder of operations.

Methodsm62e30e88a152e0e6_1528449534267_0Methods

1. Situational analysis.

2. Task contest.

Forms of workm62e30e88a152e0e6_1528449514617_0Forms of work

1. Individual work.

2. Group work.

Lesson stages

Introductionm62e30e88a152e0e6_1528450127855_0Introduction

Students revise the order of operationsorder of operationsorder of operations.

The teacher introduces the subject of the lesson – calculating values of arithmetic expressionarithmetic expressionarithmetic expression while applying the rules.

Procedurem62e30e88a152e0e6_1528446435040_0Procedure

Task 1

Students work individually, using computers. Their task is to get to know the Interactive illustration, describing the order of operationsorder of operationsorder of operations.

[Interactive illustration]

After having completed the exercise, they present results of their observations:

Operations need to be done in the following order:m62e30e88a152e0e6_1527752263647_0Operations need to be done in the following order:
1. Operations in parentheses.m62e30e88a152e0e6_1527752263647_01. Operations in parentheses.
2. Exponentiation.m62e30e88a152e0e6_1527752263647_02. Exponentiation.
3. Multiplication or division – in the order it is written.m62e30e88a152e0e6_1527752263647_03. Multiplication or division – in the order it is written.
4. Addition or subtraction – in the order it is written.m62e30e88a152e0e6_1527752263647_04. Addition or subtraction – in the order it is written.

The teacher hands out worksheets with contest tasks. Students who do the exercises correctly get grades from activity.

Task 2
In each example choose the operation that needs to be done first.

[Table]

Students do exercises using obtained knowledge.

Task 3
Calculate the arithmetic mean of numbers $2\frac{2}{14}$ and  $3\frac{6}{21}$.

Task 4
Do operations:

a. $\frac{2}{5}+0,8+(1,2-\frac{1}{2})$

b. $(\frac{5}{6}+\frac{1}{3}):(4\frac{1}{2}-3,75)$

c. $5\frac{5}{6}\cdot 4,5-2,4\cdot \frac{5}{6}$

Task 5
Write the solution by creating an arithmetic expressionarithmetic expressionarithmetic expression with many operations. Calculate and give the answer.

Tosia got 10 PLN from her mum. She bought a chocolate that cost 3,60 PLN, juice that cost 2,30 PLN and a candy bar. How much did the candy bar cost if she got 2,55 PLN of change?

The teacher evaluates the students’ work and clarifies doubts.

An extra task:
Do operations:

Lesson summarym62e30e88a152e0e6_1528450119332_0Lesson summary

Students do the revision exercises. Then together they sum‑up the classes, by formulating the conclusions to memorise.

- Arithmetic expressionarithmetic expressionArithmetic expression are expression made of numbers, signs of operations and parenthesesparenthesesparentheses.

- Operations need to be done in the following order:

1. Operations in parenthesesparenthesesparentheses.

2. ExponentiationexponentiationExponentiation.

3. MultiplicationmultiplicationMultiplication or division – in the order it is written.

4. Addition or subtraction – in the order it is written.

Selected words and expressions used in the lesson plan

arithmetic expressionarithmetic expressionarithmetic expression

divisiondivisiondivision

exponentiationexponentiationexponentiation

multiplicationmultiplicationmultiplication

operations on fractionsoperations on fractionsoperations on fractions

order of operationsorder of operationsorder of operations:
1. operations in parenthesesparenthesesparentheses,
2. exponentiationexponentiationexponentiation,
3. multiplicationmultiplicationmultiplication or divisiondivisiondivision – in the order it is written,
4. addition or subtraction – in the order it is written.

parenthesesparenthesesparentheses