Topicm882829f756df8d21_1528449000663_0Topic

Adding decimal fractions.

Levelm882829f756df8d21_1528449084556_0Level

Second

Core curriculumm882829f756df8d21_1528449076687_0Core curriculum

V. Operations on simple fractions and decimal fractions. Student:

2) adds, subtracts, multiplies and divides decimal fractions using mental maths

(in the simplest examples), or in a written form and using a calculator

(in more difficult examples);

8) performs operations on decimal fractions, using his/ her own strategies or a calculator.

Timingm882829f756df8d21_1528449068082_0Timing

45 minutes

General objectivem882829f756df8d21_1528449523725_0General objective

Performing uncomplicated calculations with mental maths skills or in more difficult examples in writing, and the use of these skills in practical situations.

Specific objectivesm882829f756df8d21_1528449552113_0Specific objectives

1. Adding decimal fractions with mental maths skills.

2. Adding decimal fractions in a written form.

3. Communicating in English, developing mathematical, scientific, technical and IT competences, developing learning skills.

Learning outcomesm882829f756df8d21_1528450430307_0Learning outcomes

The student

- performs uncomplicated addition of decimal fractions in the head.

- adds decimal fractions in a written manner.

Methodsm882829f756df8d21_1528449534267_0Methods

1. Discussion.

2. Situational analysis.

Forms of workm882829f756df8d21_1528449514617_0Forms of work

1. Group work.

2. Individual work.

Lesson stages

Introductionm882829f756df8d21_1528450127855_0Introduction

Students discuss where in everyday life we usually add decimal fractionsdecimal fractionsdecimal fractions.

The teacher gives students examples of food prices.

[Table]

On the basis of the table, students create questions and answer them.

Examples of questions:

- How much do you pay for bread and butter?

- How much do you pay for juice and a bar?

- How much do you pay for milk and cream cheese?

Students discuss how they added the appropriate decimal fractionsdecimal fractionsdecimal fractions. They answer questions.

Procedurem882829f756df8d21_1528446435040_0Procedure

Students should draw the following conclusion:

- When adding decimal fractionsdecimal fractionsdecimal fractions mentally, add the whole to the whole, and the tenth parts to the tenth parts ...

Example:

[Illustration 1]

Task

Students calculate mentally.

a) 4.25 + 2.45

b) 3.50 + 4.20

c) 4.60 + 5.20

d) 10.30 +.050

Task

Students work individually using computers. They open the slideshow and observe how we add decimals in a written method.

After finishing the task, they present the results of their observations.

[Slide show]

Students should draw the following conclusions:

- Adding decimal fractionsdecimal fractionsdecimal fractions in a written manner is done just like the written addition of natural numbersnatural numbersnatural numbers.

- The numbers should be written in such a way that the decimal points in both numbers are placed one under the other.

- We add the wholeswholeswholes to the wholeswholeswholes, tenth parts to tenth parts, hundredth parts to hundredth parts. etc.

Task

Students perform the addition of decimals in a written manner.

a) 1.46 + 12.38

b) 16.8 + 9.74

c) 42.8 + 76.49

d) 19.4 + 6.728

e) 7.28 + 14.56

Students solve the word problem. They do the addition of decimals in a written form and write down their solutions.

Task

An elderly lady is making supplies for the winter. She ordered 230.5 kg of potatoes, 27.5 kg of carrots and 12.7 kg of cabbage. How much did her shopping weigh?m882829f756df8d21_1527752256679_0An elderly lady is making supplies for the winter. She ordered 230.5 kg of potatoes, 27.5 kg of carrots and 12.7 kg of cabbage. How much did her shopping weigh?

Task

Marysia did her shopping in three stores.

In the first store she spent PLN 15.20, in the second she spent PLN 9.63 and in the last PLN 6.45. How much did she spend in total?

An extra taskm882829f756df8d21_1527752263647_0An extra task

Calculate the minuend:m882829f756df8d21_1527752263647_0Calculate the minuend:

x – 28,95 = 23,8

Lesson summarym882829f756df8d21_1528450119332_0Lesson summary

Students do the revision exercises.

Then they summarize the lesson together and formulate conclusions to remember:

- When adding decimal fractionsnatural numbersdecimal fractions mentally, add the wholeswholeswholes to the wholeswholeswholes, tenthstenthstenths to tenthstenthstenths, hundredth parts to hundredth parts etc.

- Adding decimal numbers in a written manner is done just like the column addition of natural numbersnatural numbersnatural numbers.

- The numbers should be written in such a way that the decimal points in both numbers are placed one below the other and add the wholeswholeswholes to the wholeswholeswholes, tenthstenthstenths to tenthstenthstenths, hundredthshundredthshundredths to hundredthshundredthshundredths, etc.

Selected words and expressions used in the lesson plan

decimal fractionsdecimal fractionsdecimal fractions

hundredthshundredthshundredths

natural numbersnatural numbersnatural numbers

tenthstenthstenths

wholeswholeswholes