Answer:
5.5
Explanation:
to find additional value, subtract the known
[because 4.5 plus (+) a number (m) is equal to (=) 10, the number (m) must be equal to (=) 4.5 minus (-) 10.]
10 - 4.5 = 5.5
to find if this is correct, add it back
4.5 + 5.5 = 10
m = 5.5
hope this helps:)