1. Write numbers with appropriate signs: 40∘∘C below 0∘∘C temperature.
   1. 30
   2. 40
   3. -40
   4. None of these
2. 2 subtracted from 7 gives
   1. -5
   2. 5
   3. -9
   4. 9
3. Fill in the blanks with >, < or = sign. (– 3) + (– 6) ______ (– 3) – (– 6)
   1. <
   2. >
   3. None of these
   4. =
4. The number of integers between -2 and 2 is
   1. 3
   2. 5
   3. 4
   4. 2
5. Sum of (– 9) and 15.
   1. 90
   2. -6
   3. 6
   4. 20

6. Match the following:

   Column A	Column B
   (a) 10 steps to the right	(p) -1000
   (b) 10 km below sea level	(q) 1000
   (c) Deposit Rs. 1000 in a bank	(r) 10
   (d) Spending Rs. 1000	(s) -10

7. Fill in the blanks:

   1. When we subtract -10 from 18 we get ______.
   2. _____ is an integer which is neither positive nor negative.
   3. 272 – 198 – ______ = 0.
   4. 15 + _____ =0

8. State whether the following statements are true or false:

   1. If a and b are any two integers such that a > b, then -a > – b.
   2. If the sum of an integer and its opposite is zero, then they are called additive inverses of each other.
   3. The negative of 0 is -0.
   4. The sum of positive and negative integers is always negative.

9. Write four negative integers less than –20.

10. Write all the integers between -8 and -15. (Write them in the increasing order.)

11. Find the solution of the following :(–9) + (+13)

12. Subtract :(–20) – (–13)

13. Find the value of :(–7) + (–9) + 4 + 16

14. Using number line, add the following integers: 9 + (-6).

15. The temperature on a certain morning is -11℃ at 5 a. m. If the temperature drops 3 degree at 6 a.m. and rises 5 degree at 8 a.m. and again drops 3 degree at 9 a.m. What is the temperature at 9 a.m.?

Answer

1. 3. (c) -40
      Explanation: below means less than 0 so it is – 40
2. 2. 5
      Explanation: 7 – 2 = 5
3. 1. <
      Explanation: -3 -6 = -9
      -3 – (-6) =- 3 +6 = 6- 3 = 3
      so -9 < 3
4. 1. (a) 3
      Explanation: intergers between -2 and 2 are -1,0, 1 so 3 integers
5. 3. 6
      Explanation: -9 + 15 = 15 – 9 = 6
6. 1. – (r)
   2. – (s)
   3. – (q)
   4. – ( p)
7. 1. 28;
   2. 0;
   3. 74;
   4. -15
8. 1. False
   2. True
   3. False; zero is neither negative nor positive
   4. False
9. Four negative integers less than –20 are -21, -22, -23 and – 24.
10. The integers between –8 and –15 in increasing order are –14, –13, –12, –11, –10 and –9.
11. (–9) + (+13)
    = (–9) + (+9) + (+4)
    = 0 + (+4) = +4
12. (–20) – (–13)
    = (–20) + (additive inverse of -13)
    = (–20) + (13) = –7
13. (–7) + (–9) + 4 + 16
    = (–16) + 20
    = (–16) + 16 + 4
    = 0 + 4 = 4
14. On the number line we first move 9 steps to the right from 0 reaching 9 and then we move 6 steps to the left of 9 and reach 3.
    Thus, 9 + (-6) = 3
    
15. Temperature at 5 a.m. = -11℃
    Temperature decreased at 6 a.m. = 3℃ = -3
    Temperature raised at 8 a.m. = 5℃ = +5
    Temperature decreased at 9 a.m. = 3℃ = -3
    Final temperature at 9 a.m. = (-11) + (-3) + (+5) + (-3)
    = -11 – 3 + 5 – 3
    = -17 + 5
    = -12℃.