Time to level up! Learn when and how to 'regroup' or 'carry' in addition. When ones add up to 10 or more, we trade 10 ones for 1 ten. It's like exchanging 10 pennies for 1 dime! 💰🎯
Practice the important skill of regrouping through fun, interactive challenges!
Learn to identify when regrouping is necessary in addition problems!
Practice the regrouping process with visual base-10 blocks!
Drag to sort or use ↑↓ buttons to adjust · Correct Order
Put your regrouping skills to work with real-world scenarios!
Identify correctly solved problems with regrouping!
🖱️ Drag options below to the correct boxes (computer) or click to move (mobile)
Solve complex problems that require multiple regrouping steps!
Explore 8 detailed knowledge cards covering everything you need to know about carrying and regrouping!
Regrouping (also called 'carrying' or 'trading') is what we do when a column adds up to 10 or more. Since each place can only hold digits 0-9, when we get 10 or more, we need to trade! 10 ones becomes 1 ten, which moves to the tens column. It's like exchanging 10 pennies for 1 dime - same value, different form!
When ones add to 10 or more, we 'trade' or 'regroup'
Example: 8 + 7 = 15 = 1 ten + 5 ones
The 1 ten moves to the tens column (we 'carry' it)
The 5 ones stays in the ones column
This keeps our place value organized and correct!
Remember the rule: If ones add to 10 or more, you MUST regroup! Write the ones digit in the answer, and carry the ten to the tens column. This keeps everything in the right place!
Writing both digits in the ones place! If 8 + 7 = 15, don't write '15' in the ones column. Write '5' in ones and carry '1' to tens. Each place can only hold one digit!
Like making change! If you have 15 pennies, you exchange 10 pennies for 1 dime and keep 5 pennies. Regrouping is the same idea with place value!
Use pennies and dimes to practice! Add pennies together, and whenever you get 10 or more, trade 10 pennies for a dime. This makes regrouping concrete and real!
Carrying has a specific order! First, add the ones. If you get 10 or more, break it into tens and ones. Write the ones digit in your answer and put a small '1' above the tens column (this is 'carrying the 1'). Then when you add the tens column, don't forget to add that carried 1! This systematic approach ensures accuracy every time.
Step 1: Add the ones column (if ≥10, continue to step 2)
Step 2: Break the sum into tens and ones (15 = 10 + 5)
Step 3: Write the ones digit in your answer (5)
Step 4: Carry the ten to the tens column (+1 above)
Step 5: Add the tens column including the carried digit
Write the carried digit small and above the tens column, not in your answer! This reminds you to add it later. Some students use a small circle around it so they don't forget!
Forgetting to add the carried digit when adding tens! If you carry a 1, you MUST add it to the tens column. Set up a habit: look for carried digits before adding each column!
Following a recipe step-by-step, building with instructions, or any multi-step process. The order matters! Skip a step and you'll get a wrong answer.
Color-code the steps! Use different colors for each step (red for ones, blue for carrying, green for tens). This visual system helps you remember the sequence!
Before you start adding, check if you'll need to regroup! Look at the ones digits and add them in your head. If they equal 10 or more, you know you'll need to regroup. If they equal 9 or less, you won't need to regroup. This quick check helps you prepare and stay organized!
Look at the ones: 7 + 8 = 15 (15 ≥ 10, so REGROUP!)
Look at the ones: 4 + 3 = 7 (7 < 10, so NO regrouping needed)
Look at the ones: 9 + 6 = 15 (15 ≥ 10, so REGROUP!)
Look at the ones: 5 + 2 = 7 (7 < 10, so NO regrouping needed)
The rule: If ones add to 10 or more, you must regroup!
Do a 'quick scan' before solving! Look at the ones digits: 8 + 7? That's 15, so you know you'll regroup. This mental preparation makes the actual solving smoother!
Starting without checking! Some students dive in and get surprised by regrouping. Take 2 seconds to check the ones first - it makes everything easier!
Like checking if you have enough money before shopping, or checking if you have all ingredients before cooking. Preparation prevents problems!
Play 'Regroup or Not?' - Look at addition problems and quickly say if they need regrouping, without solving! This builds instant recognition.
Regrouping is all about place value! When we have 10 or more in any place, we trade for the next larger place. 10 ones equals 1 ten. That's why when ones add to 15, we keep 5 ones and trade 10 ones for 1 ten. Understanding this trading relationship is the key to mastering regrouping!
10 ones = 1 ten (this is the trade we make!)
When we carry, we move value to the next place left
Example: 15 ones = 1 ten and 5 ones = 10 + 5
The 1 we carry represents 1 ten (worth 10)
Place value keeps our numbers organized correctly!
Think of place value like money! 10 pennies = 1 dime, 10 dimes = 1 dollar. Regrouping uses the same idea: 10 ones = 1 ten, 10 tens = 1 hundred!
Not understanding what the carried '1' represents! It's not just '1' - it's '1 ten,' which equals 10. That's why it goes in the tens column!
Making change at a store, converting between units (10 millimeters = 1 centimeter), or any situation where small units group into larger units!
Build place value charts! Draw columns for ones, tens, hundreds. Practice moving counters: when you get 10 in ones column, trade for 1 in tens column!
Where and how you write the carried digit matters! Write it small above the tens column (not mixed with other numbers). This position reminds you to add it when working on the tens column. Some teachers prefer different notations, but the key is consistency and visibility!
Write carried digits small and above the column
Example: Put small '1' above the tens column
Don't write it in the middle of your answer!
Circle or highlight it so you remember to add it
Erase or cross out after you use it (optional)
Use a different color for carried digits! Write them in pencil or a different color so they stand out. This visual reminder helps you not forget to add them!
Writing the carried digit too big, or in the wrong place, or forgetting it entirely! Keep it small, above the tens, and visible. Some students write it in their answer by mistake!
Like writing reminder notes in the margins of a page, or sticky notes on your homework. We write reminders where we'll see them when we need them!
Practice neat number writing! Use graph paper so each digit has its own square. This organization helps keep carried digits in the right spot!
Certain number combinations always require regrouping! If you memorize these patterns, you'll instantly know when to regroup. For example, any time you see 9 + something (except 0), you'll regroup. Any time you see 8 + 2 or more, you'll regroup. These patterns become automatic with practice!
8 + any number 2 or bigger needs regrouping (8+2=10)
9 + any number 1 or bigger needs regrouping (9+1=10)
7 + any number 3 or bigger needs regrouping (7+3=10)
6 + any number 4 or bigger needs regrouping (6+4=10)
5 + 5 or bigger needs regrouping (5+5=10)
Make a 'regroup chart' showing which one-digit combinations need regrouping (like 7+5, 8+3, 9+2). Keep it handy until you memorize the patterns!
Not recognizing these patterns and having to figure it out each time! Learn the patterns and regrouping becomes quick and automatic!
Pattern recognition helps in all areas of life: recognizing traffic patterns, understanding weather patterns, or noticing habits. Patterns make predictions easier!
Flashcard game! Make cards with pairs like '8+7', '6+5', etc. Practice quickly identifying which need regrouping until it's automatic!
Regrouping adds complexity, so checking is extra important! The best check is adding backwards - if 28+47=75, then 47+28 should also equal 75. You can also use subtraction to check: does 75-47=28? Yes! Or estimate: 28+47 is about 30+50=80, and 75 is close to 80. Any method that confirms your answer works!
Method 1: Add the numbers backwards (48+27 = 27+48 = 75)
Method 2: Subtract to check (75-27 = 48? Yes! ✓)
Method 3: Estimate (48+27 ≈ 50+30 = 80, close to 75 ✓)
Method 4: Add again carefully, watching for carried digits
If checks don't match, solve again slowly!
Always check regrouping problems! They're trickier, so mistakes are more common. Spend 10 extra seconds checking to catch errors before moving on!
Not checking at all, or only checking problems you're unsure about. Check EVERY regrouping problem, especially when learning! Better safe than sorry!
Double-checking important calculations (bank deposits, test scores, measurements for projects). In real life, we always verify important numbers!
Make checking a non-negotiable habit! After every problem, immediately check using a different method. It becomes automatic with consistent practice!
Regrouping happens constantly in real life! Whenever we combine amounts that sum to 10 or more in any place value, we're regrouping. Whether it's money (pennies to dimes), measurements, scores, or collections, understanding regrouping helps us calculate accurately in real situations. Math isn't just on paper - it's everywhere!
Money: 28 pennies + 47 pennies = 75 pennies (trade for 7 dimes + 5 pennies!)
Sports: Team A scored 38 points, Team B scored 27 points = 65 total points
Collections: 49 Pokemon cards + 36 new cards = 85 cards total
Cooking: Recipe needs 28 mL + 35 mL = 63 mL total liquid
Distance: Walked 47 meters, then 38 more meters = 85 meters total
Look for regrouping in your daily life! When you combine things and the total is more than 10, you're using regrouping. Recognizing it in action helps it make sense!
Thinking regrouping only exists in math class! It's actually one of the most practical skills - we use it for money, measurements, time, and more every single day!
EVERYWHERE! Shopping (adding prices), cooking (combining ingredients), games (adding scores), travel (total distances), budgeting, and more!
Create your own real-world problems! 'I have ___ toys upstairs and ___ downstairs. How many total?' Make math personal and meaningful!
Sometimes you need to regroup MORE than once in a single problem! When tens add up to 10 or more, you carry to the hundreds place just like you carried from ones to tens. It's the same process, just repeated! This shows how place value rules stay consistent as numbers get bigger.
Example: 78 + 95 requires regrouping TWICE!
Step 1: Ones → 8 + 5 = 13, carry 1 to tens
Step 2: Tens → 7 + 9 + 1 = 17, carry 1 to hundreds
Result: 173 (you regrouped from ones→tens AND tens→hundreds!)
This skill prepares you for three-digit addition!
Take it one place at a time! Don't try to do everything at once. Solve ones (carry if needed), then tens (carry if needed), then hundreds. Step by step keeps you organized!
Getting confused when you need to carry twice! Remember: each place follows the same rule. If it equals 10 or more, regroup to the next place. Simple!
Larger purchases at stores ($78 + $95), distance traveled on long trips, total points scored in multiple games - real numbers often require multiple regrouping steps!
Start with problems that need one carry, then try problems with two carries. Build up gradually. Notice the pattern - it's the same process repeated!
Regrouping seems hard at first, but with practice it becomes automatic! Every mathematician made mistakes while learning. What matters is perseverance - keep practicing, learn from errors, and celebrate small victories. Confidence comes from seeing yourself improve over time!
Start simple: Master 8+7, 9+6, 7+5 (basic regrouping)
Build up: Try 28+37, 19+46 (two-digit with regrouping)
Challenge yourself: 58+67, 78+95 (multiple regrouping)
Celebrate mistakes: Each error is a learning opportunity!
Track progress: Notice how problems that felt hard become easy!
Keep a 'success journal'! Write down problems you solved correctly each day. When regrouping feels hard, look back and see how far you've come. You're stronger than you think!
Giving up when it feels hard! Regrouping is a skill that EVERYONE can learn. If you're struggling, that means your brain is growing! Mistakes are part of learning, not a sign you can't do it.
Confidence in math builds confidence in life! When you overcome challenges in math, you learn that you can overcome challenges anywhere. This is more than math - it's building your character!
Set small, achievable goals! 'Today I'll solve 5 regrouping problems correctly.' Tomorrow, try 6. Small wins add up to big success. You've got this!