standard_description: Mentally add 10 or 100 to a given number 100–900, and mentally subtract 10 or 100 from a given number 100–900.
problem_activity: Narrative
The purpose of this activity is for students to match equations to numbers 11–19 presented on 10-frames. During the synthesis, students focus on each part of the equation and where it can be seen in the 10-frame representation of the number. When students see different parts of the equations in the 10-frame images, they look for and make use of structure (MP7).
Launch
Groups of 2
“Draw a line from each equation to the dots it matches.”
Activity
2 minutes: independent work time
3 minutes: partner work time
Student Facing
[IMG]
[IMG]
[IMG]
\(10+9=19\)
\(10+1=11\)
\(10+4=14\)
\(10+8=18\)
\(10+5=15\)
\(10+2=12\)
[IMG]
[IMG]
[IMG]
Student Response
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Activity Synthesis
Invite a student to share which image matches
\(10 + 5 = 15\)
.
“Where do you see 15 on the 10-frame?” (There are 15 dots altogether.)
“Where do you see
\(10 + 5\)
on the 10-frame?” (There are 10 dots on the 10-frame and 5 dots under the 10-frame.)


aligns: no