Instructions
Building on your mastery of two-digit addition without regrouping, this worksheet introduces the key skill of regrouping (or 'carrying over a ten') when the sum of the Ones column is 10 or more. Remember to work the Ones column before the Tens column!
Section 1: Review - Practice Without Regrouping
Now that you can solve two-digit problems easily, complete these review questions from our last worksheet.
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Solve the vertical addition problem: $52 + 17 = $
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Solve the subtraction problem (Remember to look at the Ones first): $96 - 4 = $
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Maria collected 25 seashells and her brother collected 14 seashells. How many did they collect together? Equation: Answer:
Section 2: Introducing Regrouping (Carrying a Ten)
Sometimes, when you add the Ones column, the total is 10 or more. When this happens, we must regroup. Since 10 ones make 1 ten, we move the 10 over to the Tens column.
Example: $17 + 6 = ?$
- Ones Column: $7 + 6 = 13$.
- We write the 3 in the Ones answer space.
- We carry the 1 (which is 1 ten) up to the top of the Tens column.
- Tens Column: $1$ (carried over) $+ 1 = 2$.
- Total is 23.
| T (Tens) | O (Ones) | Steps |
|---|---|---|
| ^1^ | 7 | Start: 7 + 6 = 13 |
| 1 | 6 | Write 3, Carry 1 |
| + 0 | --- | --- |
| 2 | 3 | Total: 23 |
Solve these problems using regrouping. Circle the '1' you carry over to the Tens column!
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$28 + 5 = $
-
$43 + 9 = $
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$65 + 7 = $
Section 3: Vertical Addition with Regrouping Practice
Use the chart below to practice lining up your numbers and correctly carrying the ten. The first row is done for you.
| Carry (T) | T (Tens) | O (Ones) | Problem |
|---|---|---|---|
| ^1^ | 48 + 5 | ||
| 4 | 8 | ||
| + | 0 | 5 | |
| 5 | 3 | 53 (Example) |
| Carry (T) | T (Tens) | O (Ones) | Problem |
|---|---|---|---|
| 19 + 4 | |||
| 1 | 9 | ||
| + | 0 | 4 | |
| Carry (T) | T (Tens) | O (Ones) | Problem |
|---|---|---|---|
| 36 + 7 | |||
| 3 | 6 | ||
| + | 0 | 7 | |
| Carry (T) | T (Tens) | O (Ones) | Problem |
|---|---|---|---|
| 75 + 18 | |||
| 7 | 5 | ||
| + | 1 | 8 | |
| Carry (T) | T (Tens) | O (Ones) | Problem |
|---|---|---|---|
| 29 + 29 | |||
| 2 | 9 | ||
| + | 2 | 9 | |
Section 4: Combining Skills - Real-World Application
Use the skills you've learned (no regrouping and regrouping) to solve these problems.
A. The bus had 44 students on it. At the next stop, 9 more students got on. How many students are on the bus now? Equation: Answer:
B. Ms. Davis needs 70 crayons. She already has 56 crayons. How many more crayons does she need? (Hint: Think about what number needs to be added to 56 to reach 70). Equation: Answer:
C. Leo and Mia were counting their money. Leo had 35 cents. Mia had 47 cents. If they put their money together, how much do they have in total? (This requires regrouping!) Equation: Answer:
Challenge Zone: Advanced Regrouping
C1. Find the Missing Number: $27 + 1\square = 45$. What digit belongs in the box? (Hint: $7 + \square = 15$)
C2. Double Regrouping Preview: Try adding these numbers where both the Ones and Tens columns require regrouping: $87 + 36 = $
Answer Key
Section 1: Review
- $52 + 17 = 69$
- $96 - 4 = 92$
- Equation: $25 + 14 = 39$. Answer: 39 seashells.
Section 2: Introducing Regrouping
- $28 + 5 = 33$
- $43 + 9 = 52$
- $65 + 7 = 72$
Section 3: Vertical Addition with Regrouping Practice
| Carry (T) | T (Tens) | O (Ones) | Problem |
|---|---|---|---|
| ^1^ | 19 + 4 | ||
| 1 | 9 | ||
| + | 0 | 4 | |
| 2 | 3 | 23 |
| Carry (T) | T (Tens) | O (Ones) | Problem |
|---|---|---|---|
| ^1^ | 36 + 7 | ||
| 3 | 6 | ||
| + | 0 | 7 | |
| 4 | 3 | 43 |
| Carry (T) | T (Tens) | O (Ones) | Problem |
|---|---|---|---|
| ^1^ | 75 + 18 | ||
| 7 | 5 | ||
| + | 1 | 8 | |
| 9 | 3 | 93 |
| Carry (T) | T (Tens) | O (Ones) | Problem |
|---|---|---|---|
| ^1^ | 29 + 29 | ||
| 2 | 9 | ||
| + | 2 | 9 | |
| 5 | 8 | 58 |
Section 4: Combining Skills - Real-World Application
A. Equation: $44 + 9 = 53$. Answer: 53 students. B. Equation: $70 - 56 = 14$ or $56 + 14 = 70$. Answer: 14 more crayons. C. Equation: $35 + 47 = 82$. Answer: 82 cents total.
Challenge Zone: Advanced Regrouping
C1. $27 + 18 = 45$. $7 + 8 = 15$. The digit is 8. C2. $87 + 36 = 123$ (Requires carrying the ten and then carrying the hundred).