Place value extends well beyond the thousands, millions, billions and even trillions. Although we may not see numbers beyond the trillions all that often, quantities this large do exist! This lesson teaches students the order of the period houses from thousandths to decillions. It also teaches students the reasoning behind the order, focusing on the prefix of each place value, for example, trillions begins with the prefix 'tri' which pertains to the number 3 (triangle, triple, triplets, etc.)