2nd Grade Mathematics Lesson

The Buddy System: Uncovering Even and Odd Numbers Through Pairing and Doubles

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2nd GradeBuilding Thinking Classrooms (BTC)CCSS.MATH.CONTENT.2.OA.C.3, CCSS.MATH.CONTENT.2.OA.B.250 min

Learning Objective

Students will determine whether a whole number from 1–20 is even or odd by building equal cube towers (doubles) or pairing objects, writing a corresponding doubles or doubles-plus-one equation, and articulating the ones-digit shortcut for predicting parity without building.

Lesson Overview

Students use connecting cubes and vertical whiteboards to discover that even numbers always form equal pairs with no leftovers, while odd numbers always leave one 'lonely' cube — progressing from concrete pairing to abstract ones-digit pattern recognition.

Materials

Vertical whiteboards (VNPS) or large chart paper taped to walls
Dry-erase markers (one per group)
Connecting/unifix cubes (20 per group)
Erasers or paper towels
Random grouping cards (playing cards or popsicle sticks)
Anchor chart paper and markers (teacher)
Individual mini whiteboards or paper for exit slip

Scaffolded Task Progression

1Task 1

Take

10

cubes. Can you build two towers that are EXACTLY the same height? Draw your two towers on the board and write a doubles addition equation (

x + x = 10

). Is

10

Even or Odd?

2Task 2

Now take

11

cubes. Try to build two towers of equal height. What happens? How many leftover cubes do you have? Can you write a doubles equation for

11

, or do you need a +1 at the end? Write what you find on the board.

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