Learn to regroup and carry when adding three-digit numbers! When ones or tens add up to 10 or more, we 'trade up' to the next place value. It's like exchanging coins at a bank! 💰🔄
Master regrouping with these fun, hands-on activities!
Learn to identify when regrouping is needed before solving!
Practice carrying from the ones place to the tens place!
🖱️ Drag options below to the correct boxes (computer) or click to move (mobile)
Apply regrouping to solve real addition problems!
Spot the mistakes in regrouped addition problems!
Click all correct options
Explore 7 comprehensive knowledge cards about regrouping strategies!
Regrouping (also called carrying) happens when adding two digits gives us 10 or more. We 'trade up' to the next place value - just like trading 10 pennies for 1 dime! This keeps our numbers organized and following place value rules. Regrouping is one of the most important skills in addition!
When ones add to 10 or more: Trade 10 ones for 1 ten
Example: 7 + 8 = 15 = 1 ten + 5 ones
When tens add to 10 or more: Trade 10 tens for 1 hundred
Example: 70 + 60 = 130 = 1 hundred + 3 tens
Regrouping keeps our answer organized by place value!
Write the carried number small above the next column. This reminds you to add it in! For example, write a small '1' above the tens column when you carry from ones.
Forgetting to add the carried number! If you carry a 1 to the tens place but forget to add it, your answer will be 10 too small. Always look for that little carried number!
Money exchanges! 10 pennies = 1 dime, 10 dimes = 1 dollar. When you have too many pennies, you 'regroup' them into dimes. Banks do this all day!
Use real coins! Stack 10 pennies and trade them for 1 dime. This physical regrouping helps you understand the concept perfectly!
Before solving, scan each column! If any two digits add to 10 or more, you'll need to regroup in that column. This preview helps you prepare and avoid mistakes. Remember: if the sum is 10, 11, 12, 13, 14, 15, 16, 17, or 18, you must regroup!
Look at each column: If the sum is 10 or more, regroup!
7 + 8 = 15 → Need to regroup (15 ≥ 10)
3 + 5 = 8 → No regrouping needed (8 < 10)
9 + 6 = 15 → Need to regroup (15 ≥ 10)
Check each column BEFORE you start adding the entire problem!
Do a quick 'regroup check' before solving: glance at each column and ask 'Will this add to 10 or more?' This prepares your brain for what's coming!
Not recognizing when regrouping is needed until you're already solving! Take 5 seconds to preview the problem first. It saves time and errors!
Planning: Just like checking if you have enough money before shopping, checking if you need to regroup helps you plan your work!
Play 'Regroup or Not?' - Look at pairs of numbers and quickly decide if they'll need regrouping. 8+7? Yes! 4+3? No! Practice until it's automatic!
When ones add to 10 or more, we split the number: the ones digit stays in the ones place, and we carry the tens digit to the tens column. For example, 15 = 10 + 5, so we write 5 in ones and carry 1 ten to the tens column. This is the most common type of regrouping!
Step 1: Add ones column: 8 + 7 = 15
Step 2: Ask: Is it 10 or more? Yes! (15 ≥ 10)
Step 3: Write the ones digit (5) in the answer
Step 4: Carry the tens digit (1) to the tens column
Step 5: Remember to add that carried 1 when doing tens!
Think 'write the ones, carry the tens!' For 17, write 7 and carry 1. For 13, write 3 and carry 1. For 15, write 5 and carry 1. See the pattern?
Writing both digits in the ones place! If 8+7=15, don't write 15 in your answer. Write only the 5 in ones place and carry the 1!
Counting items: If you count 17 marbles, you have 1 group of 10 plus 7 extra - that's regrouping in action!
Practice with sums from 10-18. For each sum (10, 11, 12...18), practice writing the ones digit and carrying the tens. Make flashcards!
Regrouping tens to hundreds works exactly like regrouping ones to tens - the numbers are just bigger! When tens add to 10 or more tens (100 or more), we write the tens digit and carry the hundreds digit. For example, 13 tens = 130 = 1 hundred + 3 tens.
After adding ones and any carried amount, add tens column: 7 + 6 = 13 tens
13 tens = 130 = 1 hundred + 3 tens
Write 3 in the tens place
Carry 1 to the hundreds column
This works just like regrouping ones to tens!
The process is identical to regrouping ones! If you master one type of regrouping, you've mastered them all. The only difference is the place value!
Getting confused by bigger numbers. Remember: 13 tens is just like 13 ones, but worth more. Write the 3, carry the 1 - same process!
Money: 13 dimes = 1 dollar and 3 dimes ($1.30). You've traded up from dimes to dollars - that's regrouping tens to hundreds!
Practice 'tens addition' that needs regrouping: 70+60, 80+90, 50+70. Get comfortable with these sums before doing full problems!
Some problems need regrouping in multiple places! Don't worry - handle each column one at a time. Regroup ones first, then move to tens (remembering to add any carried number), then regroup tens if needed. Take it step by step and you'll do great!
Some problems need regrouping in TWO places!
Example: 387 + 458 needs regrouping in ones AND tens
First: 7+8=15 (regroup ones to tens)
Second: 1+8+5=14 (regroup tens to hundreds - don't forget the carried 1!)
Third: 1+3+4=8 (add hundreds with the carried 1)
Stay organized! Keep track of your carried numbers by writing them clearly. Do one column completely before moving to the next. Slow and steady wins!
Losing track of carried numbers when there are multiple! Write them clearly and check each column to make sure you added any carried amount.
Big calculations like adding large amounts of money or measuring long distances often need multiple regroupings. It's a very common real-world skill!
Start with problems that need just one regrouping, then progress to double regrouping. Build confidence gradually!
Regrouping adds complexity, which means more chances for small mistakes. Always check your work! The fastest way is to add the numbers in reverse order. You can also estimate to see if your answer is reasonable - if you're adding numbers near 400 and 500, your answer should be near 900!
Method 1: Add in reverse order - if 387 + 458 = 845, then 458 + 387 should also = 845
Method 2: Estimate first - 387 ≈ 400, 458 ≈ 500, so answer should be near 900 ✓
Method 3: Use subtraction - if 387 + 458 = 845, then 845 - 458 should = 387
Method 4: Add again carefully, watching your regrouping
Always check problems with regrouping - it's easy to make small errors!
If your estimate and answer are way different, double-check your regrouping! Maybe you forgot to add a carried number or wrote the wrong digit.
Being overconfident and not checking! Even adults make regrouping errors. Smart people always verify their work!
Any important calculation - money, measurements, scores, distances - should always be checked! Accuracy matters in real life!
Make checking automatic: After solving ANY problem with regrouping, immediately check it before moving on. Build the habit!
Regrouping is one of the most important skills in elementary math! Once you master it in addition, you'll use the same concepts in subtraction, multiplication, and even algebra. Spending time to really understand regrouping now will make all future math easier. You're building a foundation!
Practice makes perfect! The more you regroup, the easier it becomes
Start with problems needing one regrouping, then progress to harder ones
Look for patterns: 8+7 always equals 15, so always needs regrouping
Build speed AND accuracy - both matter!
Celebrate your progress - regrouping is a major math milestone! 🎉
Create personal 'regroup cards' with problem pairs like 8+7, 9+6, 7+5 that always need regrouping. Quiz yourself until they're automatic!
Rushing through problems and making careless errors. Regrouping requires attention to detail. Slow down, work carefully, and check your work!
Regrouping teaches valuable life skills: breaking big problems into steps, staying organized, and checking your work. These skills transfer to everything!
Set goals! 'This week I'll master regrouping in ones place. Next week, tens place.' Breaking learning into chunks makes it manageable!