NCERT Class 7 Solutions: Integers (Chapter 1) Exercise 1.1 – Part 1

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Q-1 Following number line shows the temperature in degree Celsius Equation at different places on a particular day:

Given the number line shows temprature in degree celsius at diffrent places on a perticular day

Temprature in Degree Celsius at Different Places

Given the number line shows temprature in degree celsius at diffrent places on a perticular day

  1. Observe this number line and write the temperature of the place marked on it.

  2. What is the temperature difference between the hottest and the coldest place among the above?

  3. What is the temperature difference between Lahulspiti and Srinagar?

  4. Can we say temperature of Srinagar and Shimla taken together is less than the temperature at Shimla? Is it also less than the temperature at Srinagar?

Following figure shows operations with negative integers:

Positive and negative intergers on number line

Positive and Negative Intergers

Positive and negative intergers on number line

Rules for adding subtracting, multiplying and dividing positve and negative integers

Signs When Adding Subtracting, Multiplying and Dividing

Rules for adding subtracting, multiplying and dividing positve and negative integers

Solution:

The above scale shows temperature on a scale. The longer marks on the scale are marked at difference of Equation each small mark is at difference of Equation .

  1. Temperature and places are given in following table

    Table of temeratures of places
    Table describing the temperature of places

    Place

    Temperature (°C)

    Lahulspiti

    -8

    Srinagar

    -2

    Shimla

    5

    Ooty

    14

    Bengaluru

    22

  2. The hottest place is Bengaluru, with temperature

    Equation

    The coldest place is Lahulspiri, with temperature

    Equation

    Equation

    Equation

    Equation

  3. The temperature of Srinagar Equation

    The temperature of Lahulspiri Equation

    Equation

    Equation

    Equation

    Note that the difference is always positive.

  4. The temperature of Srinagar and Shimla Equation

    The temperature of Srinagar and Shimla Equation

    The temperature at Shimla Equation

    Since, Equation

    Thus, temperature of Srinagar and Shimla taken together is less than the temperature at Shimla.

    Now, Temperature of Srinagar Equation

    Therefore, Equation

    No, it is not less than the temperature at Srinagar.

Q-2 In a quiz, positive marks are given for correct answers and negative marks are given for incorrect answers. If Jack’s scores in five successive rounds were Equation , what was his total at the end?

Solution: If Jack’s scores in five successive rounds are Equation His total marks are Equation

Equation

Equation

Thus, Jack got 35 marks in the quiz.

Q-3 At Srinagar temperature was Equation on Monday and then it dropped by Equation on Tuesday. What was the temperature of Srinagar on Tuesday? On Wednesday, it rose by Equation what was the temperature on this day?

Solution:

  • On Monday, temperature at Srinagar = Equation

  • On Tuesday, temperature dropped = Equation

  • ∴Temperature on Tuesday Equation

  • On Wednesday, temperature rose up = Equation

  • ∴Temperature on Wednesday Equation

  • Thus, temperature on Tuesday and Wednesday was Equation and Equation respectively.

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