This document discusses place value and how the decimal system works. It explains that the decimal system uses the digits 0-9 and that the position of each digit determines its value. The value increases from right to left, so digits to the left represent larger values like thousands or millions. Place value charts can help read and understand large numbers by showing the value of each digit position. The document also covers writing numbers in standard form versus expanded form, and how to properly say large numbers aloud by naming the place value of each group.