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Percent and promil

Source: licencja: CC 0.

Procent i promil

Learning objectives

  • You will learnt to convert percents into numbers and numbers into percents and to interpret percents and promils as fractions of a whole.

Learning effect

  • You convert percents into numbers and numbers into percents and interpret percents and promils as fractions of a whole.

Revise information about percents and give examples of applying percents and promils in everyday life.

Task 1
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nagranie abstraktu

Open the slideshow and order information about percents and promils they revised at the beginning of the class.

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Pokaz multimedialny - procenty i promile. 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.

After having completed the exercise, present results of your observations and compare them with following information.

  • One percentpercentpercent (%) of a given quantity is one hundredth of this quantity.

  • To simplify, we often assume that percents are fractions whose denominator is hundredfractions whose denominator is hundredfractions whose denominator is hundred

    p%=p100
  • One promil (‰) of a given quantityone promil (‰) of a given quantityOne promil (‰) of a given quantity is one thousandth of this quantity.

  • To simplify, we often assume that promils are fractions whose denominator is thousandfractions whose denominator is thousandfractions whose denominator is thousand

    t=t1000
  • 100% is a whole,
    50% is a half,
    25% is a quarter,
    75% is three fourths,
    10% is one tenth,
    20% is one fifth,
    150% is one and a half.

Task 2
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nagranie abstraktu

Convert percents into decimal fractions and into common fractions, using ways presented in the example. Formulate an ‘instruction’ to do this conversion.

Example:

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Source: GroMar, licencja: CC BY 3.0.
  • 40%

  • 11,3%

  • 513%

Task 3
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nagranie abstraktu

Convert fractions into percents using ways presented in the example.
Formulate an ‘instruction’ to do this conversion.

Example:

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Source: GroMar, licencja: CC BY 3.0.
  • 0,38

  • 720

  • 234

Task 4
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nagranie abstraktu

Convert promils into decimal fractions and common fractions using ways presented in the example.
Formulate an ‘instruction’ to do this conversion.

Example:

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Converting promils into fractions
Source: GroMar, licencja: CC BY 3.0.
  • 11

  • 120

  • 2,5

Task 5
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nagranie abstraktu

Convert percents into promils using ways presented in the example.
Formulate an ‘instruction’ to do this conversion.

Example:

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Source: GroMar, licencja: CC BY 3.0.
  • 1,5%

  • 0,6%

  • 35%

Task 6
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nagranie abstraktu

Express following information using fractions:

  • Women are over 50% of the population of Poland.

  • Tomek read 35% of a book in one day.

  • Maciek got 85% of points at the maths test.

After having completed exercise, draw conclusions and compare them with following ones.

Conclusions:

  • To convert percentpercentpercent into fraction we need to divide the number of percents by 100 and skip the % symbol in the result.

  • To convert fraction into percentpercentpercent we need to multiply it by 100 and add the % symbol.

  • To convert promilpromilpromil into fraction we need divide the number of promils by 1000 and skip the ‰ symbol in the result.

  • To convert fraction into promilpromilpromil we need to multiply it by 1000 and add the ‰ symbol.

  • To convert percent into promilpromilpromil we need to multiply the number of percents by 10 and change the symbol % into the symbol ‰.

Task 7
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nagranie abstraktu

An extra task:

The rectangle was divided into equal parts and some of them are coloured. How many more parts we need to colour so that the white part is 30% of the rectangle?

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Source: GroMar, licencja: CC BY 3.0.

Remember:

  • One percentpercentpercent (%) of a given quantity is one hundredth of this quantity.

  • To simplify, we often assume that percents are fractions whose denominator is hundredfractions whose denominator is hundredfractions whose denominator is hundred p%=p100.

  • One promil (‰) of a given quantityone promil (‰) of a given quantityOne promil (‰) of a given quantity is one thousandth of this quantity.

  • To simplify, we often assume that promils are fractions whose denominator is thousandfractions whose denominator is thousandfractions whose denominator is thousand t=t1000.

  • To convert percentpercentpercent into fraction we need to divide the number of percents by 100 and skip the % symbol in the result.

  • To convert fraction into percentpercentpercent we need to multiply it by 100 and add the % symbol.

  • To convert promilpromilpromil into fraction we need divide the number of promils by 1000 and skip the ‰ symbol in the result.

  • To convert fraction into promilpromilpromil we need to multiply it by 1000 and add the ‰ symbol.

  • To convert percentpercentpercent into promilpromilpromil we need to multiply the number of percents by 10 and change the symbol % into the symbol ‰.

Do the revision exercises.

Exercises

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Exercise 1
Wersja alternatywna ćwiczenia: What percent of a whole is the number 78? Możliwe odpowiedzi: 1. 8,75%, 2. 87,5%, 3. 78%, 4. 87%
zadanie
Source: GroMar, licencja: CC BY 3.0.
Exercise 2

Draw any rectangle. Colour 37,5% of its surface.

Exercise 3

Wojtek divided a pizza between him and two friends. He gave each friend 13 of the pizza and 30% of the pizza to himself. Was the division fair?

Solve the exercise and justify the answer in English.

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Exercise 4
Wersja alternatywna ćwiczenia: Indicate which pairs of expressions or words are translated correctly. Możliwe odpowiedzi: 1. procent - percent, 2. promil - promil, 3. jedna setna wielkości - one hundredth of a quantity, 4. jedna tysięczna wielkości - one thousandth of a quantity, 5. zamiana procentów na ułamki - converting promils into fractions, 6. zamiana ułamków na procenty - fractions whose denominator is hundred
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

converting fractions into percents
converting fractions into percents

zamiana ułamków na procenty

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wymowa w języku angielskim: converting fractions into percents
converting fractions into promils
converting fractions into promils

zamiana ułamków na promile

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wymowa w języku angielskim: converting fractions into promils
converting percents into fractions
converting percents into fractions

zamiana procentów na ułamki

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wymowa w języku angielskim: converting percents into fractions
converting promils into fractions
converting promils into fractions

zamiana promili na ułamki

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wymowa w języku angielskim: converting promils into fractions
fractions whose denominator is hundred
fractions whose denominator is hundred

ułamki o mianowniku sto

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wymowa w języku angielskim: fractions whose denominator is hundred
fractions whose denominator is thousand
fractions whose denominator is thousand

ułamki o mianowniku tysiąc

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wymowa w języku angielskim: fractions whose denominator is thousand
one hundredth of a quantity
one hundredth of a quantity

jedna setna wielkości

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wymowa w języku angielskim: one hundredth of a quantity
one percent (%) of a quantity
one percent (%) of a quantity

jeden procent (%) danej wielkości

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wymowa w języku angielskim: one percent (%) of a quantity
one promil (‰) of a given quantity
one promil (‰) of a given quantity

jeden promil (‰) danej wielkości

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wymowa w języku angielskim: one promil (‰) of a given quantity
one thousandth of a quantity
one thousandth of a quantity

jedna tysięczna wielkości

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wymowa w języku angielskim: one thousandth of a quantity
percent
percent

procent

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wymowa w języku angielskim: percent
promil
promil

promil

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wymowa w języku angielskim: promil

Keywords

one percent (%) of a quantityone percent (%) of a quantityone percent (%) of a quantity - to setna część tej wielkości

one promil (‰) of a given quantityone promil (‰) of a given quantityone promil (‰) of a given quantity -  to jedna tysięczna tej wielkości

fractions whose denominator is hundredfractions whose denominator is hundredfractions whose denominator is hundred

fractions whose denominator is thousandfractions whose denominator is thousandfractions whose denominator is thousand