Lesson 1.4: Addition & Subtraction Strategies – 4-Digit Numbers | SEA Mathematics | My Carib Academy
SEA 2025-2028 Framework Aligned

➕➖ Lesson 1.4: Addition & Subtraction Strategies

Master addition and subtraction of 4-digit numbers. This lesson covers SEA Mathematics Objective 16 from the Number Strand.

45 Minutes
Module 1: Number
Objective 16
2 Videos
Lesson Progress 0%

Previous Lesson

Did you complete Lesson 1.3? Review Money Concepts →

Learning Objectives

By the end of this lesson, you will be able to:

  • Add 4-digit numbers with sum less than 10,000 (up to 4 addends)
  • Subtract 4-digit numbers (minuend up to 4 digits)
  • Use column addition and subtraction with regrouping
  • Solve one-step and multi-step word problems involving addition and subtraction

SEA Tip

Addition and subtraction questions appear in Section I, II, and III of the SEA Math paper. Master these to secure easy marks! (SEA Framework Page 21-22)

Watch: Addition Strategies

Start by watching this video to learn addition strategies for 4-digit numbers. Take notes as you watch! 📝

Addition Strategies (4-digit numbers) – Mathematics Video Lesson

Quick Check

Did you understand the video? Review the notes below before continuing! ✅

Addition Strategies (4-Digit Numbers)

For the SEA exam, you need to add numbers up to 4 digits with sums less than 10,000. You may have up to 4 addends!

📋 Column Addition Method:

Step-by-Step Guide
  1. Write the numbers in columns (align by place value)
  2. Start adding from the right (Ones column)
  3. If the sum is 10 or more, carry over to the next column
  4. Continue adding each column (Tens, Hundreds, Thousands)
  5. Write the final answer

📊 Example 1: Adding Two 4-Digit Numbers

3,456 + 2,789 = ?
Thousands Hundreds Tens Ones
3 4 5 6
+ 2 7 8 9
6 2 4 5

Answer: 6,245

Common Mistake

Don’t forget to carry over when the sum is 10 or more! 6 + 9 = 15, so write 5 and carry 1 to the Tens column.

Watch: Subtraction Strategies

Now watch this video to learn subtraction strategies for 4-digit numbers. Pay attention to borrowing! 🎯

Subtraction Strategies (4-digit minuend) – Mathematics Video Lesson

Subtraction Strategies (4-Digit Numbers)

For the SEA exam, you need to subtract 4-digit numbers (minuend up to 4 digits). Borrowing is key!

📋 Column Subtraction Method:

Step-by-Step Guide
  1. Write the numbers in columns (align by place value)
  2. Start subtracting from the right (Ones column)
  3. If the top number is smaller, borrow from the next column
  4. Continue subtracting each column (Tens, Hundreds, Thousands)
  5. Write the final answer

📊 Example 2: Subtracting Two 4-Digit Numbers

5,234 − 2,876 = ?
Thousands Hundreds Tens Ones
5 2 3 4
− 2 8 7 6
2 3 5 8

Answer: 2,358

Common Mistake

Don’t forget to borrow when the top number is smaller! 4 − 6 needs borrowing from the Tens column.

Word Problems

SEA loves word problems! Here’s how to solve addition and subtraction word problems.

📊 Example Word Problem:

Multi-Step Problem

Question: A school has 3,456 students. 1,234 students are boys. How many students are girls?

Solution:

  1. Total Students: 3,456
  2. Number of Boys: 1,234
  3. Number of Girls = Total − Boys
  4. Number of Girls = 3,456 − 1,234 = 2,222

Answer: There are 2,222 girls.

Check Your Work

Add the answer back: 2,222 + 1,234 = 3,456 ✓ This confirms your answer is correct!

Quick Quiz

Test your understanding! Select an answer for each question. ➕➖

6 Questions
12 Minutes
70% to Pass

1. What is 3,456 + 2,789?

2. What is 5,234 − 2,876?

3. A school has 3,456 students. 1,234 are boys. How many are girls?

4. What is 1,234 + 2,345 + 1,000?

5. When adding, what do you do if the sum is 10 or more?

6. What is 8,765 − 3,456?

0/6

Lesson Complete!

Great job finishing Lesson 1.4! You’re mastering addition and subtraction for the SEA exam! 🎉

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