Lesson 1-2: Two-Digit Addition With Regrouping

Two-Digit Addition With Regrouping

Master addition with regrouping using the stick model. Learn to carry and mark the 'carry 1' in vertical addition through birthday party scenarios.

30-35 minutesStick Model StrategyInteractive PracticeCarrying Practice

Learning Scenario: Birthday Party Balloons

The Problem:

We have 18 red balloons and 25 blue balloons for the birthday party. How many balloons do we have in total?

18 + 25 = ?

Stick Model Strategy:

Step 1: Use stick model (8 + 5 = 13)

Step 2: Bundle 10 sticks into 1 group

Step 3: Write 3 in ones place

Step 4: Carry 1 to tens place

Learning Activities

Master regrouping through interactive activities and visual demonstrations

Knowledge Points Display

Activity 1

Learn regrouping with our interactive stick model. Understand how 8 + 5 = 13 means we need to bundle 10 sticks into 1 group.

Key Features:

Interactive stick model demonstration
Visual regrouping animation
Step-by-step carrying process
Progress tracking with milestones

Skills You'll Learn:

Stick model: 8 + 5 = 13, bundle 10 sticks
Carrying: Write 3 in ones place, carry 1 to tens
Vertical addition with regrouping
Marking carry 1 above the tens column

Interactive Practice

Activity 2

Practice regrouping through birthday party balloon scenarios. Help decorate with red and blue balloons using the stick model.

Key Features:

Birthday party balloon decoration
Interactive stick model manipulation
Visual carry 1 marking
Step-by-step problem solving

Skills You'll Learn:

18 red balloons + 25 blue balloons = 43 total
Regrouping: 8 + 5 = 13, carry 1
Vertical addition with carry marking
Real-world application

Examples Library

Activity 3

Explore various two-digit addition problems with regrouping. Practice with different scenarios and number combinations.

Key Features:

Multiple regrouping problems
Visual stick representations
Step-by-step solutions
Interactive practice

Examples:

27 + 18 = 45 (7 + 8 = 15, carry 1)
39 + 26 = 65 (9 + 6 = 15, carry 1)
48 + 37 = 85 (8 + 7 = 15, carry 1)
56 + 29 = 85 (6 + 9 = 15, carry 1)

Stick Model Strategy: Step-by-Step

Example: 18 + 25

Step 1: Add ones place

8 + 5 = 13

Step 2: Bundle 10 sticks

13 = 10 + 3

Step 3: Write 3 in ones place

Carry 1 to tens place

Step 4: Add tens with carry

1 + 2 + 1 = 4

Vertical Addition with Regrouping

+25

Carry 1 marked above tens column!

Practice Problems

Try These Problems:

27 + 18 = ?

Hint: 7 + 8 = 15, carry 1

39 + 26 = ?

Hint: 9 + 6 = 15, carry 1

48 + 37 = ?

Hint: 8 + 7 = 15, carry 1

Real-World Scenarios:

Art Supplies: 29 paintbrushes + 16 markers = ? supplies

Sports Equipment: 37 basketballs + 28 soccer balls = ? balls

Classroom Chairs: 45 chairs + 17 desks = ? furniture pieces

Ready for the next lesson?

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