Adding a math type fraction to a note when using CL

Can you help me recognize that C must equal 1/6 to be correct please? Here’s what I tried. Neither one worked. This is in the CL and works fine without fractions.

correct: A=-1 and B=-1 and C=1/6 and D=6
correct: A=-1 and B=-1 and C=1\/6 and D=6

Similarly, I seem to be able to use negatives OR decimals, but not negative one half. A gives me an error here. Thank you in advance!

correct: A=-.5 and B=-2 and C=.5 and D=-6