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Solving word problems – negative numbers

Source: licencja: CC 0.

Rozwiązywanie zadań tekstowych – liczby ujemne

Learning objectives

You will develop the following competences: communicating in English, mathematical, IT and basic scientific and technical competence, your learning skills.

You will develop the ability to doing simple calculations on integers.

You will get to know a method of solving word problems with the use of negative numbers.

Learning effect

  • You will learn to do calculations on integers.

  • You will learn to solve word problems with the use of negative numbers.

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nagranie abstraktu

Revise methods of doing operations on integers. The aim of the class will be using the ability to do operations on integers to solve word problems. Solve the task using the material presented in the applet.

Task 1
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nagranie abstraktu

Solve the task below which describes the changes of the sir temperature in a town. Check the correctness of your results using the applet. In each case, decide if the temperature is positive or negative.

  1. In the morning the temperature was -4°C. In the afternoon it rose by 4°C. What was the temperature at midday?

  2. In the evening the temperature was 0°C. At midnight it dropped by 10°C. What was the temperature at midnight?

  3. At dawn the temperature was -3°C. During the day it dropped by 6°C. What was the temperature during the day?

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Aplet geogebra: Zmiany temperatury powietrza. Poniżej znajduje się galeria będąca wersją alternatywną dla aplikacji.
Source: GroMar, licencja: CC BY 3.0.
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nagranie abstraktu

What is the mathematical sense of expressions: above zero, below zero, zero or below, zero or above? Write down your conclusion.

The conclusion:

  • a number greater than zero or zero is non‑negative,

  • a number less than zero or zero is non‑positive.

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nagranie abstraktu

Solve the task below. Find a hidden word made of letters corresponding to the worked out numbers.

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nagranie abstraktu

Solve the exercises. Write the letters corresponding to the worked out numbers into the table and read the hidden word.

Task 2
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nagranie abstraktu

Exercise 1
Irek had 10 zł. He bought icecream for 6 zł, biscuits for 7 zł and a notebook for 2 zł. How much money did he have to borrow from his friend to pay for his shopping?

2 zł

3 zł

5 zł

PE

Z

L

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nagranie abstraktu

Exercise 2
Marek and Darek throw a dice in turns. For throwing the even number you get 2 points. For throwing the odd number 4 points are subtracted. Marek threw the dice three times. The first and second time he threw 5 pips and the third time he threw 4 pips. How many points has he scored if in the beginning he had 2 points?

-1

-2

-4

W

AM

IC

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nagranie abstraktu

Exercise 3
At 1 p.m. the temperature in our town was 30°C. Every hour it dropped by 20°C. What was the temperature at 5 p.m.?

-5

-4

-3

Z

A

R

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nagranie abstraktu

Exercise 4
What number will I get if I will divide -20 by -5?

-4

-2

4

A

E

B

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nagranie abstraktu

Exercise 5
A fish is swimming in the sea at a depth of 10 m. A seagull is flying above the fish, at an altitude of 6 meters above the sea level. What is the distance between the fish and the seagull?

16 m

-4 m

4 m

A

C

M

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nagranie abstraktu

Hidden word:

Exercise number

1

2

3

4

5

Letters

Task 3
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nagranie abstraktu

An extra task:
Find in the available source what an absolute zerozerozero is.

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nagranie abstraktu

Having solved all the tasks, do the consolidation tasks. Formulate the conclusion to memorize:
- a number greater than zerogreater than zerogreater than zero or zerozerozero is non‑negative,
- a number less than zeroless than zeroless than zero or zerozerozero is non‑positive.

Exercises

Exercise 1
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Wersja alternatywna ćwiczenia: Determine which sentences are true. Możliwe odpowiedzi: 1. Numbers (-2), (-7), 0 are non-positive numbers., 2. Numbers larger than (-2) are non-negative., 3. Numbers smaller (-2) are non-positive numbers., 4. Numbers 0, 1, 2, 3,… are non-negative.
Rzadanie
Source: GroMar, licencja: CC BY 3.0.
Exercise 2

In order to qualify for the final stage of the mathematical competition you need to score at least 5 points. Paweł scored consecutively: 4 pts, (-6) pts, 7 pts, (-11) pts. How many points did Paweł score altogether? Did he qualify for the final?

Exercise 3

Find out what the most popular temperature scales are. Talk about them in English.

Exercise 4
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Wersja alternatywna ćwiczenia: Indicate which pairs of expressions or words are translated correctly. Możliwe odpowiedzi: 1. liczba ujemna - negative number, 2. liczba dodatnia - positive number, 3. liczba nieujemna - non-negative number, 4. liczba niedodatnia - non-positive number, 5. temperatura powietrza - larger than zero, 6. większa od zera - non-negative number
Rzadanie
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

air temperature
air temperature

temperatura powietrza

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wymowa w języku angielskim: air temperature
greater than zero
greater than zero

większa od zera

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wymowa w języku angielskim: greater than zero
negative number
negative number

liczba ujemna

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wymowa w języku angielskim: negative number
non‑negative number
non‑negative number

liczba nieujemna

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wymowa w języku angielskim: non‑negative number
non‑positive number
non‑positive number

liczba niedodatnia

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wymowa w języku angielskim: non‑positive number
positive number
positive number

liczba dodatnia

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wymowa w języku angielskim: positive number
less than zero
less than zero

mniejsza od zera

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wymowa w języku angielskim: less than zero
zero
zero

zero

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wymowa w języku angielskim: zero

Keywords

air temperatureair temperatureair temperature

negative numbernegative numbernegative number

non‑negative numbernon‑negative numbernon‑negative number – liczba mniejsza bądź równa 0

non‑positive numbernon‑positive numbernon‑positive number – liczba mniejsza bądź równa 0

positive numberpositive numberpositive number