(-21 + 16) - (-21 - 16) = N
(-5) - ( -37) = N
(-5) + ( + 37 ) = N ⇒ Change the sign of the subtrahend, then proceed to
integers' addition rule
N = 32
The answer is 32.
Note: The question "how much more" is first value THAN the "second value" means getting their difference.
Example: How much more is 50 than 20?
Subtract:
50 - 20 = 30.
Answer: 50 is to 30 more than 20.