Topicm7d2241b451e4ecbc_1528449000663_0Topic

Operations with the decimal fractions

Levelm7d2241b451e4ecbc_1528449084556_0Level

Second

Core curriculumm7d2241b451e4ecbc_1528449076687_0Core curriculum

V. The operations with the common and decimal fractions. The student:

2) adds, subtracts, multiplies, divides the decimal fractions by mental calculation (in the simplest operations), in writing or using the calculator (in the difficult ones);

7) calculates the value of the simple arithmetic expressions using the rules of the order of operationsorder of operationsorder of operations;

8) does the operations with the decimal fractions using his own, proper strategies or using the calculator.

Timingm7d2241b451e4ecbc_1528449068082_0Timing

45 minutes

General objectivem7d2241b451e4ecbc_1528449523725_0General objective

Doing the simple operations of mental calculation or more difficult ones in writing and using these abilities in practical situations.

Specific objectivesm7d2241b451e4ecbc_1528449552113_0Specific objectives

1. Operations with the decimal fractions.

2. Solving the text tasks using the operations with the decimal fractions.

3. Communicating in English; developing mathematical and basic scientific, technical and digital competences; developing learning skills.

Learning outcomesm7d2241b451e4ecbc_1528450430307_0Learning outcomes

The student:

- solves the task using the operations with the decimal fractions,

- calculates the value of the simple arithmetic expressions.

Methodsm7d2241b451e4ecbc_1528449534267_0Methods

1. Brain storming.

2. Situational analysis.

Forms of workm7d2241b451e4ecbc_1528449514617_0Forms of work

1. Individual work.

2. Group work.

Lesson stages

Introductionm7d2241b451e4ecbc_1528450127855_0Introduction

The students revise the methods of adding, subtracting, multiplying and dividing the decimal fractions.

Procedurem7d2241b451e4ecbc_1528446435040_0Procedure

The teacher informs the students they are going to develop the ability of doing the operations with the decimal fractions in practical situations.

[Interactive graphics]

The students work individually using their computers. They are going to watch the difference between the gross weightgross weightgross weight, the net weightnet weightnet weight and the taretaretare.

The students come up with the conclusion:

The total mass of the goods including the packaging is called the gross weightgross weightgross weight.

The mass of the goods without any packaging is called the net weightnet weightnet weight.

The mass of the packaging is called the taretaretare.

The students solve the tasks using the information above.

Task 1

Ann was sent by her mum to buy some strawberries. She was given a plastic basket not to squash the strawberries on her way home. The shop assistant weighted the strawberries together with the basket. They weighted 1.754 kg. Ann said that the empty basket weighted 220 g. How much did she pay for the strawberries if the kilo of fruit costs 6 PLN?  m7d2241b451e4ecbc_1527752256679_0Ann was sent by her mum to buy some strawberries. She was given a plastic basket not to squash the strawberries on her way home. The shop assistant weighted the strawberries together with the basket. They weighted 1.754 kg. Ann said that the empty basket weighted 220 g. How much did she pay for the strawberries if the kilo of fruit costs 6 PLN?  

Task 2

The litter for cats can be bought in the packets of eight, of ten and of fifteen kilos. The bag containing eight kilos of litter costs 15PLN,  of ten kilos costs 18 PLN and of fifteen kilos costs 28 PLN.

Juliusz wants to buy 100 kilos of litter. Which type of the packaging should he choose? 

Task  3

How much should be paid for 1 kg 27 dag of tomatoes if one kilo of them costs 2.20 PLN?

Task 4

The price of the book which was 32 PLN fell over 8%. How much money did the price go down? How much is the book after the discount?

Task 5

If you pay the money for the deposit, the bank offers 6% of the initial deposit after a year. How much money will the bank offer after a year of the deposit of 12 120 PLN?

An extra task:

Become familiar with the information given by the bricklayers from the 17Indeks górny th^th century and nowadays.

The bricklayer form the 17Indeks górny th^th century: “ I earn 20 grosz a day. 1PLN equals 30 grosz.
The shoes are 1PLN 20 grosz. Korzec of rye costs 3 PLN”.

The bricklayer nowadays: “I earn 80 PLN a day.1 PLN equals 100 grosz.
The shoes are 150PLN. The kilo of the rye costs 80 grosz”.

KORZEC – it is former Polish measure of the volume which equals 128 litres. Korzec of the rye
weights 90 kg.

How many days did the bricklayer in the 17Indeks górny th^th century have to work to buy the shoes, and have many days does he have to work nowadays?

How many kilos of rye was the bricklayer able to buy un the 17Indeks górny th^th century for his daily income and how many kilos can he buy nowadays?

Lesson summarym7d2241b451e4ecbc_1528450119332_0Lesson summary

The students do the summarising tasks.

Then they sum up the class drawing the conclusions to memorise:

- The total mass of the goods including the packaging is called the gross weight.
- The mass of the goods without any packaging is called the net weight.
- The mass of the packaging is called the tare.m7d2241b451e4ecbc_1527752263647_0- The total mass of the goods including the packaging is called the gross weight.
- The mass of the goods without any packaging is called the net weight.
- The mass of the packaging is called the tare.

Selected words and expressions used in the lesson plan

gross weightgross weightgross weight

net weightnet weightnet weight

taretaretare

increaseincreaseincrease

decreasedecreasedecrease

order of operationsorder of operationsorder of operations

promotionspromotionspromotions