Answer: OPTION A. 5
Explanation:
The value of MN is the distance between M and N.
Distance formula on number line: | value 1-value 2 |
Since distance is always positive we use absolute value. This means, that in contents of this question, M-N or N-M does not make any difference in result.
M=-3
N=2
-------------------------------------------------------------
| value 1-value2 |
=| M-N |
=| -3-2 |
=| -5 |
=5
--------------------------------------------------------------
As a matter of fact, it is a number line, so you can just count the number of gaps in between.