6)
a)
A positive number that would fit between 1 and -1 is 0.5, and
a negative number that would fit between 1 and -1 is -0.5.
b)
The only whole number between -0.5 and 0.9 is 0, and its opposite is also 0.
c)
A decimal between -4 and -3 can be -3.4.
A fraction could be -7/2 (in decimal: -3.5)