standard_description: Use addition and subtraction within 20 to solve word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.
problem_activity: Narrative
The purpose of this activity is for students to write a
\(10 + n\)
expression that is equal to a given expression. Each expression given has three addends, two of which make a ten.
Required Materials
Materials to Gather
Connecting cubes or two-color counters
Double 10-frames
Launch
Groups of 2
Give students access to double 10-frames and connecting cubes or two-color counters.
“Now you will write a
\(10 + n\)
expression with the same value as each of the given expressions.”
Activity
5 minutes: independent work time
3 minutes: partner discussion
Student Facing
Write a
\(10 + \boxed{\phantom{3}}\)
expression that has the same value as each expression.
\(5 + 7 + 5\)
\(3 + 7 + 6\)
\(1 + 9 + 9\)
\(4 + 8 + 6\)
\(8 + 10 + 2\)
If you have time, write as many expressions as you can with 3 numbers that are equal to
\(10 + 5\)
.
Student Response
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Activity Synthesis
Display each
\(10 + n\)
expression.
“In order to make adding three numbers easier, we can rewrite each expression as a
\(10 + \boxed{\phantom{3}}\)
expression.”
Invite students to say the value of each
\(10 + n\)
expression together.


aligns: no