Lesson Plan: Two-Digit by Two-Digit Addition
Grade Level: 1
Subject: Math
Duration: 50 minutes
1. Learning Objectives
By the end of this lesson, students will be able to:
- Represent and solve two-digit plus two-digit addition problems within 100 using place-value models (base-ten blocks) and drawings.
- Explain the steps of adding tens and ones, including making a ten when necessary.
2. Standards Alignment
- CCSS.MATH.CONTENT.1.NBT.C.4 Add within 100, including adding a two‐digit number and a two‐digit number, using concrete models or drawings and strategies based on place value.
- CCSS.MATH.CONTENT.1.NBT.C.5 Given a two‐digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
3. Materials & Resources
- Sets of base‐ten blocks (tens rods and one‐unit cubes), one per student pair
- Place‐value mats labeled “Tens” and “Ones”
- Whiteboard & markers
- Individual whiteboards and dry‐erase markers for students
- 2‐digit addition worksheet (5 problems)
- Exit tickets (1 problem each)
- Chart paper with example problem
- Visual number line (0–100)
- Sentence frames for ELLs (e.g., “____ tens + ____ tens = ____ tens.”)
4. Instructional Activities & Teaching Strategies
A. Hook / Number Talk (5 minutes)
- Display two numbers (e.g., 23 and 15) on the board.
- Ask: “How many tens? How many ones? What strategies might help us add these quickly?”
- Listen for responses like “Group the ones first,” “Make a ten,” or “Count on.”
B. Direct Instruction (10 minutes)
- Model with base‐ten blocks on chart paper: – Place 23 (2 rods, 3 cubes) on the mat. – Place 15 (1 rod, 5 cubes) beside it.
- Demonstrate combining ones: 3 cubes + 5 cubes = 8 cubes.
- Combine tens rods: 2 rods + 1 rod = 3 rods.
- Show final sum: 38.
- Repeat with a “making a ten” example (e.g., 27 + 18), highlighting regrouping of 10 ones into 1 ten rod.
C. Guided Practice (15 minutes)
- Pair students; give each pair base‐ten blocks + place‐value mat.
- Project Problem #1 on whiteboard (e.g., 34 + 22).
- Students model together, teacher circulates, prompts: – “How many ones?” – “Do we need to make a ten?” – “What is our total?”
- Discuss whole‐class responses, using sentence frames for scaffolding.
- Repeat with Problems #2 and #3, gradually releasing responsibility to students.
D. Independent Practice (15 minutes)
- Distribute individual whiteboards and worksheet (Problems #4–#5).
- Students solve two 2-digit addition problems using either: – Base‐ten blocks (if needed) – Drawing tens/ones – Mental strategy (for early finishers)
- Teacher circulates, offers support, and notes misconceptions.
E. Closure & Exit Ticket (5 minutes)
- Ask a volunteer to demonstrate one problem at the board.
- Distribute exit ticket: a single two‐digit addition problem (e.g., 46 + 29).
- Collect tickets for quick formative assessment.
5. Assessment Methods
- Formative: Observation during guided/independent practice, anecdotal notes, whiteboard checks
- Exit Ticket: Single problem to verify individual understanding
- Student Explanations: Use sentence frames to assess verbal explanation of steps
6. Differentiation Strategies
- Struggling Learners – Continue use of manipulatives; work in a 3-student support group – Provide number-line visuals and one-on-one mini-lessons – Offer partially completed place‐value mats
- English Language Learners – Provide sentence frames and word banks (e.g., “ones,” “tens,” “total”) – Use pair-share so they can rehearse language – Label manipulatives in students’ home languages if possible
- Advanced Learners – Challenge with word problems requiring two-digit addition (e.g., “If Sara has 47 stickers and she buys 36 more, how many does she have?”) – Introduce adding three two‐digit numbers or mental adding of 10 more/less (standard 1.NBT.C.5)
7. Lesson Timeline
|
Time |
Component |
Activity |
|
0–5 min |
Hook / Number Talk |
Pose 23 + 15; elicit strategies |
|
5–15 min |
Direct Instruction |
Model with base‐ten blocks; demonstrate regrouping |
|
15–30 min |
Guided Practice |
Pairs solve 3 problems with teacher support |
|
30–45 min |
Independent Practice |
Students complete 2 problems on whiteboards/worksheet |
|
45–50 min |
Closure & Exit Ticket |
Volunteer demo; exit ticket collection |
This 50-minute lesson uses hands‐on modeling, guided practice, and formative assessments to ensure that first graders master two-digit by two-digit addition in alignment with Common Core standards.