The roles of punctuation marks while learning about written numbers

Twenty-three kindergarten and first grade children were asked to articulate the meaning and the need for punctuation marks in a list of numerals showing prices for a list of items. Despite not having been schooled yet formally on the use and roles of numerical punctuation, many children gave similar explanations regarding the purpose of punctuation marks in numerals, including: to separate, to mark the type of number (e.g., price), to denote value, to make it a different number, and to read the number differently. Each of these explanations is a partial description of the conventional use of these marks within written numbers. These findings provide evidence that children are, in fact, creating and recreating ideas about different aspects of written numbers such as the role of punctuation marks before necessarily being able to fully articulate how written numbers work and before being formally taught, though they have obviously been exposed from an early age to these particular aspects of written numbers.