Page 24 - Revised Maths Wisdom Class - 6
P. 24
22 MATHS
Integers are used in real-life context widely. Some of the common examples are here:
Altitude
As we have learned, to measure the height of a mountain or the depth of a sea, the sea level is taken as reference
point and is considered to be the zero level. Hence, the height of Mt. Everest of 8848 m implies that it is 8848 m
above sea level. Similarly, the depth of an ocean will be represented as –250 m if it is 250 m below the sea level.
Temperature
Look at the temperature on a particular day for the metropolitan cities in the world and you will see numbers as
25°C, –5°C, etc. This implies the temperature is 25°C above 0°C and 5° below 0°C. Here the melting point of ice
or 0°C is taken as a reference point.
Profit and Loss
In business mathematics, a profit of ` 50 is expressed as +50 whereas loss of ` 15 is shown as –15. To know more
about it, check the share prices news in the newspaper.
Absolute Value of an Integer
Whether we represent temperature, distance or profit and loss, there is a change in the value. For example moving
up on the mountain for 15 metres or going down in the sea for 15 metres, the distance is covered in both the
cases, i.e., 15 units. Hence the absolute of +15 and –15 is 15. The absolute value of an integer is the distance of
that integer from 0 irrespective of negative or positive sign. The absolute values of –7 and +7 both are denoted
as | 7 | which is equal to 7.
Credit and Debit Concepts
Suppose you want to open a bank account in a local bank with the ` 2000 that you had been saving over the last
month. Your bank balance therefore starts at ` 2000.
And if you do the entry in your passbook this amount shows as credit amount or in simple way, if you deposit
amount in your account that amount refers to credit amount.
If you pay your mobile bill of `199 from your bank account. This is shown in your bank passbook as a ‘debit’.
The amount taken from your account is referred as debit amount.
‘Credits’ as positive numbers and ‘debits’ as negative numbers. The total of all your credits (positive numbers)
and debits (negative numbers) is your total bank account balance. This can be positive or negative!
Representation of Integers on Number line
We have already learned to represent whole numbers on number line and if you have noticed we represent it as:
0 1 2 3 4 5 6 7 8
Whole numbers are extended towards right side of 0, we can extend this number line towards left side too as
shown here:
–7 –6 –5 –4 –3 –2 –1 0 1 2 3 4 5 6 7
Negative integers Zero Positive integers
Observe the number line carefully and see that –2 < –1 whereas 2 > 1 i.e., as we move towards left on the integer
number line, the number becomes smaller. Interestingly, if we assume there exists a mirror at zero, the image of
