If we denote the height of a place above sea level by a positive integer and depth below the sea level by a negative integer, write the following using integers with the appropriate signs:

a) 200 m above sea level

b) 100 m below sea level

c) 10 m above sea level

d) sea level

Match the items of Column I with that of Column II:

Compute each of the following:

(a) 30 + (–25) + (–10)

(b) (–20) + (–5)

(c) 70 + (–20) + (–30)

(d) –50 + (–60) + 50

(e) 1 + (–2) + (– 3) + (– 4)

(f) 0 + (– 5) + (– 2)

(g) 0 – (–6) – (+6)

(h) 0 – 2 – (–2)

Write the opposite of each of the following:

a) Decrease in size

b) Failure

c) Profit of Rs.10

d) 1000 A.D.

e) Rise in water level

f) 60 km south

g) 10 m above the danger mark of river Ganga

h) 20 m below the danger mark of the river Brahmaputra

i) Winning by a margin of 2000 votes

j) Depositing Rs.100 in the Bank account

k) 20°C rise in temperature.

Temperature of a place at 12:00 noon was + 5°C. Temperature increased by 3°C in first hour and decreased by 1°C in the second hour. What was the temperature at 2:00 pm?