# SUBTRACTING NEGATIVE RATIONAL NUMBERS

We can use number line to subtract negative rational numbers.

If we subtract a negative rational number, we have to move in the positive direction on the number line.

For example, if we want to subtract -0.5 from 5, we have to move 0.5 units from 5 in the positive direction.

Example 1 :

Subtract -1.5 from 2.5.

Solution :

Step 1 :

Since we subtract the negative rational number -1.5 from 2.5, we have to move 1.5 units from 2.5 in the positive direction on the number line.

It has been illustrated in the picture given below. Step 2 :

After having moved 1.5 units in the positive direction from 2.5, we are in the position of 4.

So,

2.5 - (-1.5)  =  4

Example 2 :

Subtract -2.5 from -2.

Solution :

Step 1 :

Since we subtract the negative rational number -2.5 from -2, we have to move 2.5 units from -2 in the positive direction on the number line.

It has been illustrated in the picture given below. Step 2 :

After having moved 2.5 units in the positive direction from -2, we are in the position of 0.5

So,

-2 - (-2.5)  =  0.5

Example 3 :

During the hottest week of the summer, the water level of the Muskrat River was 5/6 foot below normal. The following week, the level was 1/3 foot below normal. What is the overall change in the water level ?

Solution :

Subtract to find the difference in water levels. That is, we have to find -1/3 - (-5/6)

Step 1 :

Since we subtract the negative rational number -5/6 from -1/3, we have to move 5/6 units from -1/3 in the positive direction on the number line.

It has been illustrated in the picture given below. Step 2 :

After having moved 5/6 units in the positive direction from -1/3, we are in the position of 1/2.

So, the water level changed 1/2 foot. Apart from the stuff given above, if you need any other stuff in math, please use our google custom search here.

You can also visit the following web pages on different stuff in math.

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