Breaking a Ten!
Chapter 7: Subtraction With Borrowing
Sometimes we don't have enough ones to subtract. What do we do? We open a bundle of ten! One ten becomes ten ones — we're not taking extra, just rearranging what we have.
Not Enough Stickers!
Riya wants to give away some stickers. 🌟
"I have 42 stickers. I want to give 18 stickers."
Milo looks worried. "Wait! You only have 2 loose ones. You need to give 8!"
Riya smiles. "I'll open a bundle! One ten becomes ten ones."
First, let's remember when subtraction is easy — when we have enough ones!
💡 The key question: "Do I have enough ones?" When the answer is YES, we don't need to borrow!
Let's try: 42 − 18
⚠️ We can't just subtract! 2 − 8 doesn't work. We need help from the tens place.
We don't take extra — we reorganise what we already have.
🔓 Key insight: 4 tens + 2 ones = 3 tens + 12 ones. Same total, different arrangement!
42 − 18 = ?
When we write borrowing, we show: cross out the old, write the new
💡 Check: Ones: 12 − 8 = 4 ✓ | Tens: 3 − 1 = 2 ✓ | Answer: 24
52 − 27 = 25
Milo's work: 4 tens + 12 ones → 12−7=5, 4−2=2
What's wrong with Milo's work?
💡 The real world: Whenever you "break" something big into smaller parts to share — that's borrowing in action!
Questions & Answers
Breaking a ten
Why do I sometimes need to break a ten?
Because the ones you have are not enough to take from. You open one bundle so the ones place gets ten more.
What does breaking a ten really do?
It renames the number without changing it. 42 becomes 3 tens and 12 ones. Still 42, just packed differently.
How do I do 52 take away 27?
The 2 ones cannot give 7. Open one ten. Now you have 4 tens and 12 ones. 12 take away 7 is 5. 4 tens take away 2 tens is 2 tens. Answer 25.
Is anything lost when I break a ten?
No. One ten leaves the tens place and ten ones arrive in the ones place. The total stays exactly the same.
Why is the tens digit one smaller afterwards?
Because one bundle was opened and moved. It did not disappear. It is now sitting in the ones column as ten ones.
What if the tens are zero, like in 40?
Then 40 is 3 tens and 10 ones. You open one of the four tens. The 4 becomes 3 and the ones become 10.
Why is this called regrouping?
Because you regroup the same amount into different sized parts. Grouping and regrouping is the whole idea of place value.
How do I check my answer?
Add the answer to the number you took away. 25 plus 27 is 52. If it matches your start, you did it right.
💜 Signs of readiness: Child confidently asks "Do I have enough ones?" before starting. Child understands 1 ten = 10 ones. Child can explain why the total stays the same after regrouping.
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