Reasoning and Proving
The reasoning process supports a deeper understanding of mathematics by enabling students to
make sense of the mathematics they are learning. The process involves exploring phenomena,
developing ideas, making mathematical conjectures, and justifying results. Teachers draw on
students’ natural ability to reason to help them learn to reason mathematically. Initially, students
may rely on the viewpoints of others to justify a choice or an approach. Students should be
encouraged to reason from the evidence they find in their explorations and investigations or
from what they already know to be true, and to recognize the characteristics of an acceptable
argument in the mathematics classroom. Teachers help students revisit conjectures that they
have found to be true in one context to see if they are always true. For example, when teaching
students in the junior grades about decimals, teachers may guide students to revisit the
conjecture that multiplication always makes things bigger