Katie eats 1/3 of the remaining pizza when 3/4 of it is left. What mathematical topic must students learn to understand this problem?

To understand the problem of Katie eating 1/3 of the remaining pizza when 3/4 of it is left, students need to grasp the concept of subtraction of fractions with like denominators. The scenario starts with a fraction (3/4) and involves taking a portion of that fraction (1/3 of 3/4).

In mathematical terms, when you eat 1/3 of something that is represented as a fraction (in this case, 3/4 of the pizza), you are essentially calculating a fraction of a fraction. This requires an understanding of how to manipulate fractions, specifically in cases where they share the same denominators or can be adjusted to have like denominators.

When students learn to subtract fractions with like denominators, they develop a foundational skill for combining or comparing fractional parts, which is pivotal for solving problems involving portions of quantities, such as in this scenario. This knowledge allows students to accurately calculate how much pizza Katie actually eats and how much remains afterwards.