Erika Isomura describes the first time she introduced her students to naming for decimal place value, which was 12 days into working with patterns in fraction and decimal representations. Mia comments that in more traditional approaches to mathematics instruction, naming decimal place value might be the starting place.

Erika points out to her students that the root of the word “decimal” means 10, and she reminds her students of their existing knowledge about place value in quantities greater than 1 (10, 100, 1,000, and so on).

Her students could name the decimal place values, connect these place value names to the fractions, and explain that each fraction represents dividing by 10.

Erika then asked why there aren’t any “parts” for the ones place.

Mia and Erika discuss how many of their own more solid conceptual understandings of mathematics didn’t develop until adulthood, and how they both work to shore up students’ understandings in ways that Mia and Erika didn’t experience themselves as children.

5th Grade Math – Decimal Place Value*Erika Isomura, Glassbrook Elementary School, Hayward Unified School District, Hayward, California*

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