Ariana has 2/3 quart of milk. she uses 3/4 of it in a recipe. how much milk did ariana use in her recipe?

To find a fraction of a fraction, what you have to do is multiply. You're looking for  of  so you're equation is going to be 

×   = 

To multiply fractions, you multiply straight across (numerator x numerator, denominator x denominator):
×   =  quart or  quart

This makes more sense when you draw a picture. First starting by drawing what you're taking a fraction of, which is . Then you split the entire whole into fourths to find what  is. See the attached picture. :)

She has 2/3 quart and only used 3/4 of it.

If she had used twice as much, you'd multiply by 2, but instead, she used only 3/4 of it, so you'll only need to multiply her amount by 3/4, like so:

2/3*3/4 = (2*3)/(3*4) = 6/12 = 1/2

Answer is: 1/2 quart

The answer should be : -0.3