Couple ways to skin that cat...
Use Data: Text to Columns. You can just hit finish since you want space delimited and that is the default. This will split the data into two columns, side by side, with the units e.g. 5km and 120m. At this point, you can do find and replace on both columns to remove the units.
The other is to manipulate by formulas. These formulas to the right of your cells should do the trick. There are probably other formulas or even other strategies but these are what first came to mind. Let me know if you have any questions.
For data in A1, put these in B1 and C1:
Code:
=VALUE(LEFT(A1,FIND("km",A1)-1))
Code:
=VALUE(MID(A1,FIND(" ",A1)+1,FIND("m",A1,FIND(" ",A1))-FIND(" ",A1)-1))