Math Mammoth Place Value 4 is a short worktext is a worktext covering place value and large numbers up to 1 million. The book is meant primarily for fourth grade. The first lessons only deal with thousands, or numbers with a maximum of four digits. These are for review and for deepening the student’s understanding of place value, since it is crucial that the student understands place value with four-digit numbers before moving on to larger numbers. Then, larger numbers will be very easy to study. The lessons then go on to teach numbers up to one million. Students write numbers in expanded form, compare them, add and subtract them, and learn more about rounding. Lastly, we briefly study the multiples of 10, 100, and 1,000 and multiplying numbers by 10, 100, and 1,000. These lessons prepare the way for some very important ideas that students encounter when they study multi-digit multiplication (also a topic of fourth grade math).