The level of the surface of oceans or seas is called the sea level. Land and hills are raised and are at some height from the sea level. City A is $10 \mathrm{m}$ below sea level, City B is $28 \mathrm{m}$ below sea level and City C is $14 \mathrm{m}$ above sea level.

Aditi uses the following rules to represent the elevation of different locations.

The sea level is considered to be zero elevation.

Below sea level is shown using the ‘$–$’ sign.

Above sea level is shown using the ‘$+$’ sign.

For example, the elevation of City A is shown as $–10$.

What would be the elevation of City B?

The level of the surface of oceans or seas is called the sea level. Land and hills are raised and are at some height from the sea level. City A is $10 \mathrm{m}$ below sea level, City B is $28 \mathrm{m}$ below sea level and City C is $14 \mathrm{m}$ above sea level.

Aditi uses the following rules to represent the elevation of different locations.

The sea level is considered to be zero elevation.

Below sea level is shown using the ‘$–$’ sign.

Above sea level is shown using the ‘$+$’ sign.

For example, the elevation of City A is shown as $–10$.

The elevation of City D is $1 \mathrm{m}$ above the elevation of City B. What is the elevation of City D? 

A submarine at the depth of $45 \mathrm{m}$ rises to $20 \mathrm{m}$ below sea level.

What is the depth of the submarine after rising?

A diver at the depth of $60 \mathrm{m}$ spotted a seaweed $23 \mathrm{m}$ below him.

What is the depth of the seaweed from the sea level?

$8–8=0$ Which of the following is true for the numbers shown above?

The figure shows the position of the satellite above earth. PR is the line joining the satellite and the centre of earth. P is the position of the satellite, Q is a point on the surface of earth and R is the centre of earth.

The distance between P and Q is $1300 \mathrm{km}$ and the distance between the centre of earth and the satellite is $7671 \mathrm{km}$.

What is the distance between the points Q and R?

The figure shows the position of the satellite above earth. PR is the line joining the satellite and the centre of earth. P is the position of the satellite, Q is a point on the surface of earth and R is the centre of earth.

The distance between P and Q is $1300 \mathrm{km}$ and the distance between the centre of earth and the satellite is $7671 \mathrm{km}$.

Shobhit marks Q as zero and the direction from Q to P is positive. What is the distance of R with reference to P?

The picture below shows the control panel of a lift in a mall.

‘$0$’ is the ground loor. The two-wheeler parking area ‘$-1$’ is at basement level $1$ and the car parking area ‘$-2$’ is at basement level $2$.

Ahmed enters the lift at Floor $3$ and exits at the two-wheeler parking area. How many loors did the lift go down?

The picture below shows the control panel of a lift in a mall.

‘$0$’ is the ground floor. The two-wheeler parking area ‘$-1$’ is at basement level $1$ and the car parking area ‘$-2$’ is at basement level $2$.

Meera entered the lift at the car parking floor. She pressed ‘$6$’ on the control panel of the lift. How many floors up does she want to go?