NCERT Class 7 Solutions: Integers (Chapter 1) Exercise 1.1 – Part 1
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Q1 Following number line shows the temperature in degree Celsius at different places on a particular day:

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

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

What is the temperature difference between Lahulspiti and Srinagar?

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

Temperature and places are given in following table
Table of Temeratures of Places Table describing the temperature of placesPlace
Temperature (°C)
Lahulspiti
8
Srinagar
2
Shimla
5
Ooty
14
Bengaluru
22

The hottest place is Bengaluru, with temperature
The coldest place is Lahulspiri, with temperature

The temperature of Srinagar
The temperature of Lahulspiri
Note that the difference is always positive.

The temperature of Srinagar and Shimla
The temperature of Srinagar and Shimla
The temperature at Shimla
Since,
Thus, temperature of Srinagar and Shimla taken together is less than the temperature at Shimla.
Now, Temperature of Srinagar
Therefore,
No, it is not less than the temperature at Srinagar.
Q2 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 , what was his total at the end?
Solution: If Jack’s scores in five successive rounds are His total marks are
Thus, Jack got 35 marks in the quiz.
Q3 At Srinagar temperature was on Monday and then it dropped by on Tuesday. What was the temperature of Srinagar on Tuesday? On Wednesday, it rose by what was the temperature on this day?
Solution:

On Monday, temperature at Srinagar =

On Tuesday, temperature dropped =

∴Temperature on Tuesday

On Wednesday, temperature rose up =

∴Temperature on Wednesday

Thus, temperature on Tuesday and Wednesday was and respectively.