Answer:
¹/₄
Explanation:
Given:
- Daughter = 1/8 of the dessert.
- Son = 1/4 of the dessert.
- Husband = 3/8 of the dessert.
The dessert is the "whole", i.e. equal to 1.
To find how much of the dessert was left, subtract all the given portions from 1:

Therefore, ¹/₄ of the dessert was left for Sara.