The Montessori math activity-Formation of Decimal Numeral Cards helps children to develop an understanding of the decimal system and place value. Through this activity, children learn how the position of a digit in a number affects its value and how to create and order decimal numbers from thousands to units. By using the decimal numeral cards, children can visualize and manipulate the numbers, making the abstract concepts of place value and decimal numbers more concrete and tangible. This hands-on approach helps children develop a solid foundation for more complex math concepts in the future.