- Books Name
- CBSE Class 6 Mathematics Book

- Publication
- Param Publication

- Course
- CBSE Class 6

- Subject
- Mathmatics

**Subtraction of Integers with the help of a Number Line**

We have added positive integers on a number line. For example, consider 6+2. We start from 6 and go 2 steps to the right side. We reach at 8. So, 6 + 2 = 8.

We also saw that to add 6 and (–2) on a number line we can start from 6 and then move 2 steps to the left of 6. We reach at 4. So, we have, 6 + (–2) = 4.

Thus, we find that, to add a positive integer we move towards the right on a number line and for adding a negative integer we move towards left. We have also seen that while using a number line for whole numbers, for subtracting 2 from 6, we would move towards left.

i.e. 6 – 2 = 4

**Ex.1 ** Find the value of – 8 – (–10) using number line

**Sol.: ** – 8 – (– 10) is equal to – 8 + 10 as additive inverse of –10 is 10.

On the number line, from – 8 we will move 10 steps towards right.

We reach at 2. Thus, –8 – (–10) = 2

**Hence, to subtract an integer from another integer it is enough to add the additive inverse of the integer that is being subtracted, to the other integer.**

**Ex.2 **Subtract the sum of 998 and – 486 from the sum of – 290 and 732.

**Sol.** Sum of 998 and – 486 is 998 + (– 486) = (998 – 486) = 512

Sum of – 290 and 732 is – 290 + 732 = 732 – 290 = 442

Now, 442 – 512 = 442 +(–512) = – 70

[We subtract 442 from 512 and give minus sign to the result]

**Ex.3 ** On a particular day, the temperature at Dehradun at 10 AM was 20ºC but by midnight , it fell down to 11ºC. The temperature at Bangaluru at 10AM the same day was 30º C but fell down to 18º C by the midnight . Which fall is greater ?

**Sol. ** Fall in temperature at Dehradun = 20ºC – 11ºC = 9ºC

Fall in temperature at Bangaluru= 30ºC – 18ºC = 12ºC

*∴*The fall in temperature at Bangaluru is greater and is 12ºC.