Add and subtract fractions with like denominators using models and symbols
Grab Bag
Description Students begin by working with preselected sets of rods and determine the value of the smaller rods, where the longest rod is the whole. They then add these together to determine the sum. Next, students randomly select a collection of rods from a baggie/paper bag and use the largest rod in their selection as the whole to determine the fractional value of the collection (e.g., if blue is the longest rod, blue is
9
9
and the value of all the rods is
21
9
). 

Mathematics Using relational rods, students add fractional quantities when the whole is dependent upon the length of the longest rod selected. This helps students to think flexibly about unit fractions by changing the whole from one trial to the next. This task builds conceptual understanding of unit fractions as well as intuitive understanding of addition of fractions with a common denominator. 

Curriculum Connections Students will:


Instructional sequence


Highlights of student thinking Students may:

Key questions


Materials

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