if you dont understand the concept of a negative number, i suggest looking up and using a number line.
another way to look at it
7.6 = 6+1.6
subtracting 6 +1.6 from 6 can be written as the expressiong
6-( 6+1.6)
distribution property
6-6-1.6
6-6 =0 so the result is -1.6
