standard_description: Fluently add and subtract within 20 using mental strategies. (See standard 1.OA.6 for a list of mental strategies.) By end of Grade 2, know from memory all sums of two one-digit numbers.
problem_activity: Narrative
The purpose of this activity is for students to find the missing value in addition and subtraction equations. This activity is optional because determining the missing value of an equation is not required by the standards. Students may “just know” some of the answers or they may use counting forward or backward (MP7) or they may draw a picture.
MLR8 Discussion Supports.
Invite students to read their completed equations aloud.
Advances: Listening, Speaking
Required Materials
Materials to Gather
Connecting cubes or two-color counters
Launch
Groups of 2
Give students access to connecting cubes or two-color counters.
Display the student book.
“What do you notice? What do you wonder?” (The equations have a number missing. Why are there numbers missing?)
30 seconds: quiet think time
1 minute: partner discussion
Share responses.
“FIll in the missing part of each equation.”
Activity
10 minutes: partner work time
Monitor for students who use two-color counters or connecting cubes.
Monitor for students who draw pictures.
Student Facing
Fill in the missing part of each equation.
\(3 - \underline{\hspace{1.1 cm}} = 2\)
\(2 + \underline{\hspace{1.1 cm}} = 2\)
\(5 - \underline{\hspace{1.1 cm}} = 2\)
\(1 + \underline{\hspace{1.1 cm}} = 2\)
\(5 - \underline{\hspace{1.1 cm}} = 3\)
\(2 + \underline{\hspace{1.1 cm}} = 3\)
\(4 - \underline{\hspace{1.1 cm}} = 3\)
\(0 + \underline{\hspace{1.1 cm}} = 3\)
\(5 - \underline{\hspace{1.1 cm}} = 4\)
\(3 + \underline{\hspace{1.1 cm}} = 4\)
\(4 - \underline{\hspace{1.1 cm}} = 4\)
\(2 + \underline{\hspace{1.1 cm}} = 4\)
\(1 + \underline{\hspace{1.1 cm}} = 5\)
\(4 + \underline{\hspace{1.1 cm}} = 5\)
\(5 - \underline{\hspace{1.1 cm}} = 5\)
\(3 + \underline{\hspace{1.1 cm}} = 5\)
Student Response
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Activity Synthesis
Invite previously identified students to share.


aligns: no