MathIsimple
Lesson 1-2: Three-Digit Subtraction

Three-Digit Subtraction

Master three-digit subtraction with regrouping and decomposition methods through interactive farm animal count scenarios.

45 minutesRegrouping StrategiesFarm ScenariosDecomposition Method
Learning Scenario: Farm Animal Count

The Problem:

A farm has 523 chickens total. If 176 are hens, how many roosters are there?

Farm Animal Subtraction Challenge

Step-by-Step Method:

Step 1: 3 - 6, need to borrow from tens
Step 2: 12 - 6 = 6 ones
Step 3: 1 - 7, need to borrow from hundreds
Step 4: 11 - 7 = 4 tens, 4 - 1 = 3 hundreds

Learning Activities

Master three-digit subtraction through interactive activities and real-world scenarios

Knowledge Points Display
Activity 1
Learn three-digit subtraction with our friendly math teacher. Master regrouping and decomposition methods through interactive demonstrations.

Key Features:

  • Interactive regrouping demonstration
  • Step-by-step decomposition process
  • Visual subtraction strategies
  • Progress tracking with milestones

Skills You'll Learn:

  • Regrouping: Borrow 1 from tens to make 10 ones
  • Decomposition: Break numbers into parts
  • Vertical subtraction: Line up digits correctly
  • Problem solving: Apply to real scenarios
Interactive Practice
Activity 2
Practice three-digit subtraction through farm animal count scenarios. Help calculate remaining animals and manage farm inventory.

Key Features:

  • Farm animal count simulation
  • Interactive subtraction practice
  • Regrouping strategy application
  • Real-world problem solving

Skills You'll Learn:

  • 523 - 176 = 347 roosters (with regrouping)
  • Step 1: 3 - 6, borrow from tens
  • Step 2: 12 - 6 = 6 ones
  • Step 3: 1 - 7, borrow from hundreds
Examples Library
Activity 3
Explore various three-digit subtraction problems and practice different regrouping scenarios.

Key Features:

  • Multiple problem types
  • Different regrouping scenarios
  • Step-by-step solutions
  • Interactive practice problems

Examples:

  • No regrouping: 456 - 234 = 222
  • Tens regrouping: 523 - 176 = 347
  • Hundreds regrouping: 612 - 389 = 223
  • Both regrouping: 800 - 456 = 344
Regrouping Guide: Step-by-Step

Regrouping Rules:

Rule 1: Borrow from tens

When ones column needs more

Rule 2: Borrow from hundreds

When tens column needs more

Rule 3: Always cross out and write

Cross out the digit you're borrowing from

Example: 523 - 176

Step 1: Borrow from tens

3 - 6 → 13 - 6 = 7 ones

Step 2: Borrow from hundreds

1 - 7 → 11 - 7 = 4 tens

Step 3: Subtract hundreds

4 - 1 = 3 hundreds

Answer: 347

523 - 176 = 347

Decomposition Method

Decomposition Steps:

Step 1: Break down the number

523 = 400 + 110 + 13

Step 2: Subtract each part

110 - 70 = 40, 13 - 6 = 7

Step 3: Add the results

400 + 40 + 7 = 447

Farm Example:

Total chickens: 523

Hens: 176

Roosters: 523 - 176 = 347

Check: 347 + 176 = 523 ✓

Practice Examples

Farm Animal Problems:

Chickens - Hens: 523 - 176 = 347 roosters

Cows - Calves: 456 - 189 = 267 adult cows

Pigs - Piglets: 312 - 145 = 167 adult pigs

Sheep - Lambs: 678 - 234 = 444 adult sheep

Regrouping Scenarios:

No Regrouping: 456 - 234 = 222

Tens Regrouping: 523 - 176 = 347

Hundreds Regrouping: 612 - 389 = 223

Both Regrouping: 800 - 456 = 344

Ready for the next lesson?

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