You would write AB with a horizontal line segment over the letters A and B
So you would write this 
If you cannot draw that on your computer, then I would stick to saying "segment AB".
Given that volume is:
V=s³
where:
s=side length
The volume of a cube whose side length, s=3/4 yards will be given by:
V=(3/4)³
Simplifying this we get:
V=27/64 yd³
Answer: 27/64 yd³
the answer to your question is -12
$0.66 / 0.3% = 2.2
Check:
2.2 * 0.3 = 0.66
Hope this helps!