Topicmd04189748580733f_1528449000663_0Topic

Comparing decimal fractions

Levelmd04189748580733f_1528449084556_0Level

Second

Core curriculummd04189748580733f_1528449076687_0Core curriculum

IV. Common and decimal fractions. The student:

7) marks and reads common and decimal fractions on the number line;

8) writes down decimal fractions in the form of ordinary fractions;

9) converts common fractions of denominators being the divisor of numbers 10, 100, 1000 etc into finite decimal fraction using any method (simplifying or extending common fractions, dividing the numerator by the denominator, with the long method or the calculator)

12) compares fractions (ordinary and decimal).

Timingmd04189748580733f_1528449068082_0Timing

45 minutes

General objectivemd04189748580733f_1528449523725_0General objective

Performing simple calculations in memory or more difficult operations using the long methods, and applying this skills in practical situations.

Specific objectivesmd04189748580733f_1528449552113_0Specific objectives

1. Simplifying and extending decimal fractions.

2. Comparing decimal fractions.

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

Learning outcomesmd04189748580733f_1528450430307_0Learning outcomes

The student:

1. Simplifies and extends decimal fractions.

2. Compares decimal fractions.

Methodsmd04189748580733f_1528449534267_0Methods

1. Discussion.

2. Situational analysis.

Forms of workmd04189748580733f_1528449514617_0Forms of work

1. Work with the whole class.

2. Individual work.

Lesson stages

Introductionmd04189748580733f_1528450127855_0Introduction

Students revise the rules of comparing common fractions of the same denominators.

- If two fractions have the same denominators then the one that has a greater nominator is greater.

Task

Students compare common fractions

a) $\frac{3}{10}$ and $\frac{7}{10}$

b) $\frac{5}{100}$ and $\frac{2}{100}$

c) $\frac{152}{1000}$ and $\frac{265}{1000}$

Proceduremd04189748580733f_1528446435040_0Procedure

Task

Students compare decimal fractions by convertingconvertingconverting them into common fractions. They write down the conclusions they draw by doing this task.

a) 0.23 i 0.52

b) 0.252 i 0.123

c) 0.5 i 0.54

Conclusions

- To compare decimal fractions we can convert them into common fractions and follow the rules introduced before.

- If after convertingconvertingconverting them into common fractions they have different denominators, we can extend them to find the common denominatordenominatordenominator, for example $0,5=\frac{5}{10}=\frac{50}{100}=0,50$.

Task

Students compare decimal fractions by convertingconvertingconverting them into common fractions. They write down the conclusions they draw after having completed the exercise.

a) 0.5 i 0.50

b) 0.300 i 0.3

c) 0.70 i 0.700

d) 0.60 i 0.6

Conclusions

- Adding zeros after the pointpointpoint at the end of decimal fractiondecimal fractiondecimal fraction does not change its value – it is extending the decimal fractiondecimal fractiondecimal fraction by 10, 100, 1000…

- Deleting zeros at the end of the decimal fractiondecimal fractiondecimal fraction does not change its value – it is simplifying the decimal fractiondecimal fractiondecimal fraction by 10, 100, 1000…

Task

Students work individually using computers. They open the slideshow and observe how we compare decimal fractions using the number line. After having completed the exercise, they present the results of their observations.

[Slide show]

 Students should draw the following conclusions

- To compare two decimal fractions first we compare their whole parts and then their fractional parts.

- The easiest way to compare fractional parts is to extend or simplify the fractions so that they have the same number of digits after the pointpointpoint.

Task

Students compare the decimal fractions using the conclusions above.

a) 2.365 i 2.362

b) 0.258 i 0.358

c) 32.25 i 3.225

d) 0.365 i 0.0365

e) 1.235 i 1.2

Task

Students order the numbers in the decreasing order

1.6; 0.7; 1.9; 0.6; 0.65; 1.12.

An extra task

Write three fractions greater than 0.4 and smaller than 0.5.md04189748580733f_1527752263647_0Write three fractions greater than 0.4 and smaller than 0.5.

Lesson summarymd04189748580733f_1528450119332_0Lesson summary

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

- To compare decimal fractions we can convert them into common fractioncommon fractioncommon fractions and follow the rules introduced before.

- Adding zeros after the pointpointpoint at the end of decimal fractiondecimal fractiondecimal fraction does not change its value – it is extending the decimal fraction by 10, 100, 1000…

- Deleting zeros at the end of the decimal fractiondecimal fractiondecimal fraction does not change its value – it is simplifying the decimal fraction by 10, 100, 1000…

- To compare two decimal fractions first we compare their whole parts and then their fractional parts.

- The easiest way to compare fractional parts is to extend or simplify the fractions so that they have the same number of digits after the pointpointpoint.

Selected words and expressions used in the lesson plan

common fractioncommon fractioncommon fraction

convertingconvertingconverting

decimal fractiondecimal fractiondecimal fraction

denominatordenominatordenominator

pointpointpoint