Answer:
0.4
Explanation:
The numbers -3.5 and -3.1 have a difference in value of 0.4
An easy way to look at this is to remove the decimal points. 35 - 31 is equal to 4, so that would make the difference 0.4.
Because both numbers are negative, the x must be a positive.
Therefor, 0.4 - 3.5 = -3.1