On the 124th day of school, young mathematicians are asked to find out how many days are left in the 180-day school year. The teacher version to the task offers several ways the problem can be solved, and can be used to guide instruction on different problem-solving methods.

Concepts

addition, tens, base 10, hundreds chart, hundreds, counting backward, counting by 10, skip counting, counting

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Additional Tags

math

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Instructional Ideas

• Use on or around the 124th day of school to make the situation relevant
• Put learners in pairs and assign them different methods for solving, such as on a number line, hundreds board, using base-ten blocks, and counting on and backwards. Then have them present their methods to the class

Classroom Considerations

• Requires a class set of hundreds boards and base-ten blocks, and assumes that pupils are familiar with using both
• Modify the task as necessary to extend challenge learners

Pros

• The task allows second graders to choose their method for solving (base-ten blocks, hundreds board, counting on, counting backward)
• Focuses on subtracting three-digit numbers with regrouping

Cons

• None

Common Core

2.NBT.B.7