Question 859054
The whole recipe requires 4 cups of vinegar. If Sandy were to make 1/5 of the recipe, she would need 1/5 (one fifth) of the vinegar necessary for the whole thing.
This is done by dividing 4 cups with 5.
1/5 of 4 cups of vinegar = 1/5 * 4 cups or 4/5 = 0.8
She would need 4/5 or 0.8 of a cup of vinegar.