Reflection: Intervention and Extension Find a Match! - Section 4: Independent Practice


Upon talking to a few students in my extension group and looking through their work after the lesson, I saw a few kids that had some misconceptions in how to solve a number sentence like 20 + 30 + 2. For example, one student explained that he solved it like this: 

Jakarin: I know 20+30 is 50.

Me: How do you know 20+30 is 50?

Jakarin: I can count like this: 10, 20, 30, 40, 50 (showing fingers as he counts).

Me: Ok, is the answer 50?

Jakarin: No. I need to add the 2. 

Me: Show me how to do that.

Jakarin: 50, 60, 70.

Me: Are we adding tens? 

Jakarin: No, we are adding 2 more ones.

Me: How can we add 2 more ones.

Jakarin: 50, 60, 70.

Me: How would we need to count to make sure we are adding 2 more ones? 

Jakarin: Oh! 50, 51, 52!


This misconception about adding tens vs. ones is really important for setting them up for the 2nd grade Operations and Algebraic Thinking standards, where they need to be able to add within 100 in word problems. I am going to pull this group and talk with them briefly about it before tomorrow's lessons and show them what Jakarin did. We can use base 10 blocks (students need concrete models in first grade) to show his thinking more. Then I'll have them explain what mistake Jakarin made and how to fix it. Using student work helps all students learn more!

  Possible Base 10 Misconceptions
  Intervention and Extension: Possible Base 10 Misconceptions
Loading resource...

Find a Match!

Unit 10: Solving 3 Addend Problems
Lesson 5 of 8

Objective: SWBAT match number sentences that are equal. SWBAT combine 2 addends that equal 10 to help them solve a 3 addend number sentence.

Big Idea: Students practice equality and 3 addend number sentences in this fun, interactive partner game!

  Print Lesson
2 teachers like this lesson
find a match
Similar Lessons
Addition Strategies
1st Grade Math » Single Digit Addition and Subtraction
Big Idea: Let’s put it all together! In this lesson students will use addition strategies to solve word problems.
Lakeland, FL
Environment: Urban
Lisa Murdock
What's the Sum
1st Grade Math » Blending
Big Idea: Old McDonald had a farm and all of his animals came out to play. How many animals are there in all? Today the students will find out!
Waitsfield, VT
Environment: Suburban
Thomas Young
Word problems with 3 Addends Part I
1st Grade Math » Word Problems
Big Idea: Following multi-step directions is a difficult task for first graders. This introductory lesson will teach them how to bring a word problem to life and help them visualize what needs to be done to solve by joining three numbers.
Oklahoma City, OK
Environment: Urban
Jennifer Moon
Something went wrong. See details for more info
Nothing to upload