Subtraction patterns over increasing place values
key notes :
🔸 Subtraction Involves Place Value
- In subtraction, we subtract ones from ones, tens from tens, and hundreds from hundreds.
👉 Example: 456 − 123
Hundreds: 4−1 | Tens: 5−2 | Ones: 6−3
🔹 Patterns With Tens (−10, −20, −30…) 🔢✨
- When we subtract 10, only the tens place changes.
- Ones stay the same!
🧮 Example:
65 − 10 = 55
65 − 20 = 45
65 − 30 = 35
🟣 Pattern: The number decreases by 10 each time!
🔸 Patterns With Hundreds (−100, −200…) 💯📉
- When we subtract 100, only the hundreds place changes.
- Tens and ones stay the same!
🧮 Example:
345 − 100 = 245
345 − 200 = 145
🟢 Pattern: The number decreases by 100 every time!
🔹 Recognizing Subtraction Pattern Steps 👀📊
- Numbers form a sequence when subtracting the same value repeatedly.
Example Pattern:
➡️ 300, 250, 200, 150, 100
👉 Each step subtracts 50
🔸 Use Place Value to Simplify Subtraction 💡🧮
- Break subtraction into parts:
Example: 534 − 120
= (500 − 100) + (30 − 20) + 4
= 400 + 10 + 4
✅ = 414
🔹 Borrowing/Regrouping May Be Needed 🔁✍️
- When a smaller digit is on top, we regroup from the next place value.
Example:
402 − 189
👀 Borrow from tens/hundreds if needed.
🧩 Spot the Pattern Activity Tip 💬📝
Ask students:
✔️ What number is being subtracted each time?
✔️ Which place value is changing?
✔️ What remains the same?
🌈 Quick Examples:
| Pattern | Subtracted Value | Sequence |
|---|---|---|
| Tens Pattern | −10 | 89, 79, 69, 59 |
| Hundreds Pattern | −100 | 650, 550, 450, 350 |
| Mixed Pattern | −25 | 200, 175, 150, 125 |
🎯 Key Idea to Remember
💬 “When you subtract by 10s or 100s, look at the place value that changes. Others stay the same!”
Learn with an example
Complete the pattern:
9 −____= 5
90 −____= 50
900 −____= 500
9,000 −____= 5,000
Find the first missing number:
9 ones − 4 ones = 5 ones
9 − 4 = 5
Now complete the pattern:
9 tens − 4 tens = 5 tens
90 − 40 = 50
9 hundreds − 4 hundreds = 5 hundreds
900 − 400 = 500
9 thousands − 4 thousands = 5 thousands
9,000 − 4,000 = 5,000
Complete the pattern:
____− 5 = 4
____− 50 = 40
____− 500 = 400
____− 5,000 = 4,000
Find the first missing number:
9 ones − 5 ones = 4 ones
9 − 5 = 4
Now complete the pattern:
9 tens − 5 tens = 4 tens
90 − 50 = 40
9 hundreds − 5 hundreds = 4 hundreds
900 − 500 = 400
9 thousands − 5 thousands = 4 thousands
9,000 − 5,000 = 4,000
Complete the pattern:
______− 6 = 1
______ − 60 = 10
______− 600 = 100
Find the first missing number:
7 ones − 6 ones = 1 one
7 − 6 = 1
Now complete the pattern:
7 tens − 6 tens = 1 ten
70 − 60 = 10
7 hundreds − 6 hundreds = 1 hundred
700 − 600 = 100
Let’s practice!
