Owing (being in debt) $2 can be represented by
-2. Adding -2 and 6 together can be shown like this:
-2 + 6 = 4 |
Adding To a Negative Integer
The example above shows adding a positive integer to a negative integer
by moving to the right on a number line.
Adding a Negative Integer
The example below shows adding a negative integer to a positive integer
by moving to the left on a number line.
Think of adding a negative number the same as being given
a fine - the end result is that you will have less!
More Examples of Adding With Negative Integers
Subtracting With Negative Numbers
Subtracting From Negative Integers
When subtracting positive numbers using a number line we move to the
left on the line.
Subtracting Negative Integers
When subtracting negative numbers we move to the
right. Moving to the left by a negative number is the same as moving
to the right by the opposite positive number.
What would you do if someone asked you to walk
-3 miles to the north?
You could walk 3 miles to the south! |
Changes in Temperature
Depending where you live you might experience temperatures below zero
degrees. In such cases integers are useful for showing temperature
and changes in temperature. For example, if the temperature during
the day is 16 degrees and overnight it falls to -9 degrees, by how
much did the temperature change?
-9 - 16 = -25
Another way is to think how far -9 is from zero
and how far 16 is from zero.
Once we work out these as being 9 and 16 we can
add them together to get a difference of -25 (we use the negative
sign because the temperature is falling.) |
Try these worksheets:
|
Adding
Integers