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Division of the common fractions

Source: licencja: CC 0.

Dzielenie ułamków zwykłych

Learning objectives

You will discover the methods of division the common fractions.

Learning effect

  • You convert the natural number by the common fraction.

  • You divide the fraction by the fraction.

  • You specify the reciprocal of given number.

  • You solve the task using the division of the fractions.

  • You use English to describe the method of dividing common fractions.

Today you are going to discover the method of dividing the common fractions.

Prepare two sets of cards with numbers from 1 to 9. Draw two cards of the first set and make the common fractioncommon fractioncommon fraction of it. The letter of the first card is the numerator, the letter of the other card is the denominator of the fraction. Use the pencil as a fraction bar. Then, use the other set of the cards to make such a fraction that the product of both fractions equals 1.

Conclusion:

If the product of two fractions different from zero equals 1 , they are reciprocal of one another.

Task 1
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nagranie abstraktu

Complete the table:

The reciprocals of the numbers.

Number

The reciprocal of a number

56

1

3

There is not the reciprocal

47

58

Conclusion:

  • The number 0 has not the reciprocal.

  • The reciprocal of number 1 is 1.

Analyse the example below.

The cake was divided into identical parts, each of them was 16 part of the cake. How many pieces was the cake divided into?

1:16=6

Answerm6901f5edee07edc1_1533277756654_0Answer

Watch the slideshow. You are going to learn the method of division the natural numbernatural numbernatural number by the mixed numbermixed numbermixed number.

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Pokaz slajdów przedstawia w jaki sposób dzielimy liczbę naturalną przez liczbę mieszaną. Instrukcja obsługi z poziomu klawiatury: 1. Uruchomienie aplikacji - ENTER, 2. Na każdym ze slajdów czytany jest automatycznie tekst alternatywny po polsku, 3. Przy pierwszym uruchomieniu na pierwszym slajdzie, czytanie tekstu po angielsku - TAB, 4. Przejście między slajdami: do następnego slajdu - TAB, do poprzedniego slajdu - TAB + SHIFT, 5. Przejście do czytania napisu po angielsku - strzałka w górę + strzałka w dół (czyta tekst po angielsku widoczny na slajdzie).
Source: GroMar, licencja: CC BY 3.0.

Conclusion:

To divide the natural numbernatural numbernatural number by the fraction, the number should be multiplied by the reciprocal of the fraction.

The students divide the natural numbers by the mixed numbers.

Task 2
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nagranie abstraktu

Calculate:

  1. 3:213

  2. 7:112

  3. 10:345

Conclusion:

To divide the natural numbernatural numbernatural number by the mixed numbermixed numbermixed number we should convert the mixed numbermixed numbermixed number to the improper fraction first, then divide the natural number by the fraction.

Look at the example below:

34:57=34·75=3·74·5=2120=1120

Conclusion:

To divide the common fractioncommon fractioncommon fraction by the other common fractioncommon fractioncommon fraction we should multiply the first fraction by the reciprocal of the second one.

Task 3
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nagranie abstraktu

Calculate:

  1. 49:57

  2. 37:914

  3. 178:234

Conclusion:

When the dividend or the divisor is a mixed numbermixed numbermixed number it should be converted to the improper fraction.

Task 4

An extra task:

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nagranie abstraktu

The division of given number firstly by 34, then by 45 can be substituted by a fraction. Find out that fraction.

Remember:

  1. If the product of two fractions different from zero equals 1, they are reciprocal of one another. To divide the natural numbernatural numbernatural number by the fraction , the number should be multiplied by the reciprocal of the fraction.

  2. To divide the natural numbernatural numbernatural number by the mixed numbermixed numbermixed number we should convert the mixed numbermixed numbermixed number to the improper fraction first, then divide the natural numbernatural numbernatural number by the fraction.

  3. To divide the common fractioncommon fractioncommon fraction by the other common fractioncommon fractioncommon fraction we should multiply the first fraction by the reciprocal of the second one.

  4. When dividend or divisor is a mixed numbermixed numbermixed number it should be converted to the improper fraction.

Check what you have learned by doing the following tasks.

Exercises

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Exercise 1
Wersja alternatywna ćwiczenia: Determine which sentences are true. Możliwe odpowiedzi: 1. 57:1521=1, 2. 49:212:116:117=215, 3. 411:1333:23=12
Exercise 2

There were 2 litres of orange juice in the jug. Ann poured the juice into identical glasses with volume of 14 of a litre. How many glasses did she pour the juice into?

Exercise 3

Grandmother made 1212 of litre of fruit compote. She will pour it into the jugs with volume of 114 of litre each. How many jars should she prepare to pour all the compote into?

Exercise 4
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Wersja alternatywna ćwiczenia: Indicate which pairs of expressions or words are translated correctly. Możliwe odpowiedzi: 1. iloraz - quotient, 2. odwrotność liczby - reciprocal of the number, 3. liczba mieszana - mixed number, 4. ułamek zwykły - common fraction, 5. liczba naturalna - reducible fraction, 6. mnożenie ułamka - the simplest form
zadanie
Source: GroMar, licencja: CC BY 3.0.
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Interaktywna gra, polegająca na łączeniu wyrazów w pary w ciągu jednej minuty. Czas zaczyna upływać wraz z rozpoczęciem gry. Jeden ruch to odkrywanie najpierw jednej potem drugiej karty z wyrazem. Każdy wyraz jest odczytywany. Kolejny ruch to odkrywanie trzeciej i czwartej karty. W ten sposób odsłuchasz wszystkie wyrazy. Nawigacja z poziomu klawiatury za pomocą strzałek, odsłuchiwanie wyrazów enterem lub spacją. Znajdź wszystkie pary wyrazów.
Source: Zespół autorski Politechniki Łódzkiej, licencja: CC BY 3.0.

Glossary

common fraction
common fraction

ułamek zwykły

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wymowa w języku angielskim: common fraction
irreducible fraction
irreducible fraction

ułamek nieskracalny – ułamek, którego nie można skrócić

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wymowa w języku angielskim: irreducible fraction
mixed number
mixed number

liczba mieszana

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wymowa w języku angielskim: mixed number
multiplication of the fraction
multiplication of the fraction

mnożenie ułamka

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wymowa w języku angielskim: multiplication of the fraction
natural number
natural number

liczba naturalna

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wymowa w języku angielskim: natural number
quotient
quotient

iloraz

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wymowa w języku angielskim: quotient
reciprocal of the number
reciprocal of the number

odwrotność liczby

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wymowa w języku angielskim: reciprocal of the number
reducible fraction
reducible fraction

ułamek nieskracalny

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wymowa w języku angielskim: irreducible fraction
the simplest form
the simplest form

najprostsza postać

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wymowa w języku angielskim: simplest form

Keywords

common fractioncommon fractioncommon fraction

mixed numbermixed numbermixed number

natural numbernatural numbernatural number

quotientquotientquotient

reciprocal of the numberreciprocal of the numberreciprocal of the number

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