Fractions
Keri pours 6 glasses of juice. Each glass holds 3/4 cup.
This means that there are 6 times 3/4 cups:

When we multiply an integer with a fraction, we just have to multiply it by the numerator:

Since 6 x 3 = 18:

Simplification
We can simplify 18/4 since both 18 and 4 can be divided by 2:
18 ÷ 2 = 9
4 ÷ 2 = 2
Then,

Since 2 fits 4 times on 9 (4 times 2 is 8) and there is one left over, we can write the fractions 9/2 as:

Answer: 4 1/2 cups.