Precisely measured equally segmented bars known as Number Rods give four year old children in the Montessori prepared environment the keys to the world of mathematics. By physically counting each segment within a given Number Rod, children receive a clear impression of quantity as an isolated entity. This action combined with guidance from the trained Montessori teacher provides a solid foundation of numbers one through ten in preparation for all future mathematical studies. Written and illustrated by AMI Diploma holder Mary Da Prato, My First Montessori Book of Quantities isolates Number Rods "One" through "Ten" and labels each with its corresponding numerical symbol to reinforce at home the earliest math activities children learn in the Casa.