This document discusses counting patterns with 3-digit numbers. It introduces counting by 1s, 10s, 25s, 50s, and 100s and defines key terms like counting patterns. Examples are provided of counting by 2s, 10s, and 100s using 3-digit number sequences. Critical thinking questions ask the reader to determine numbers based on clues about being a certain number of ones, tens, or hundreds more or less than another number.