Adding with Regrouping
Grade 4 students learn multi-digit addition with regrouping in Saxon Math Intermediate 4. When a column sums to 10 or more, students write the ones digit and carry the tens digit to the next column. Adding 58 plus 24: the ones column gives 8 + 4 = 12, so write 2 and carry 1; the tens column gives 1 + 5 + 2 = 8 for a final answer of 82. The most common mistake is forgetting to include the carried digit in the next column. This Chapter 1 foundational skill is the building block for all multi-digit addition and connects to regrouping in larger addition problems.
Key Concepts
New Concept When we add, we sometimes have to regroup because we cannot have a number larger than $10$ as the sum of any place value.
What’s next Next, you’ll see how this works with money and then apply the same method to add multi digit numbers using pencil and paper.
Common Questions
What is regrouping in addition?
Regrouping means carrying a digit to the next place value column when a column sum reaches 10 or more. For 58 plus 24, the ones column gives 12 — write 2 in the ones place and carry 1 to the tens column.
How do you add 58 plus 24 with regrouping?
Ones column: 8 + 4 = 12. Write 2 in the ones place and carry 1. Tens column: 1 (carry) + 5 + 2 = 8. Write 8 in the tens place. Answer: 82.
Why is regrouping also called carrying?
When a column sum reaches 10 or more, you carry the tens digit to the top of the next column to the left, like physically carrying it over. The carried digit represents groups of 10 being traded for one larger unit.
What is the most common regrouping mistake?
Forgetting to add the carried number. After writing the carry at the top of the next column, students must include it in the column sum. Forgetting the carry in 58 + 24 gives 5 + 2 = 7 instead of 1 + 5 + 2 = 8, producing the wrong answer 72.
What Saxon Math chapter introduces addition with regrouping?
Addition with regrouping is introduced in Saxon Math Intermediate 4, Chapter 1 (Lessons 1-10), as a foundational arithmetic skill.