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About this Grade 2 Addition With Regrouping Drill

Addition with regrouping is a crucial bridge skill that helps second graders move beyond simple single-digit facts to solving real-world problems. When your child adds 27 + 15, they're learning to combine tens and ones strategically—a foundational concept for all future math. This skill develops number sense and shows children that 10 ones can become 1 ten, building flexible thinking about how numbers work. At ages 7-8, students' brains are ready to hold multiple steps in mind, making this the perfect time to introduce regrouping. Mastering addition with regrouping now makes subtraction, multiplication, and multi-digit problems accessible in third grade and beyond. Children who can regroup confidently also develop confidence in math itself, seeing that they can tackle bigger numbers and more complex problems.

What your student will practice

• Add two-digit numbers using the regrouping (carrying) strategy correctly
• Identify when 10 ones must be exchanged for 1 ten
• Write regrouped numbers in the ones and tens places accurately
• Explain why regrouping is necessary in addition problems

Common mistakes to watch for

The most common error is forgetting to add the regrouped ten to the tens column—children add 27 + 15, correctly regroup 12 ones into 1 ten and 2 ones, but then write 2 in the tens place instead of 4. Another frequent mistake is writing both the regrouped ten AND the original tens without combining them, creating answers like 312 instead of 42. Watch for students who write the carried ten too small or in the wrong spot, or who lose track of the ones after regrouping. If your child's answers don't match expected sums or seem randomly wrong, check whether they're performing the regroup step but forgetting to add it to the tens column.