2-Digit Addition (with Regrouping)
Practise adding two-digit numbers, including the all-important step of regrouping — carrying a ten into the next column.
Practice now
How to add two-digit numbers
Two-digit addition is where place value and the addition facts come together. The method is short, and the one new idea is regrouping (carrying): when a column adds up to 10 or more, the extra ten moves into the next column.
- Add the ones column first.
- If the ones add up to 10 or more, write the ones digit and carry the ten above the tens column.
- Add the tens column, including any carried ten.
- Write the result — done.
Worked examples
Tips & common mistakes
Line the numbers up by place value — ones under ones, tens under tens — and always start from the ones column, not the left. A quick estimate checks the result: 47 + 38 is about 50 + 40 = 90, so 85 looks right.
- Adding from the left instead of the ones column — the carry only works right-to-left.
- Forgetting to add the carried ten into the tens column.
- Misaligning the digits so ones and tens get mixed up.
Frequently asked questions
What is regrouping in addition?
When a column adds to 10 or more, you write its ones digit and carry the ten into the next column to add on. It is the same idea as “carrying.”
What grade is 2-digit addition?
It is a grade 2 skill, building on the addition facts learned in grades K-1.
Do the addition facts need to be solid first?
Yes — each column is just an addition fact, so quick recall makes this much smoother.
How do we check the answer?
Round and estimate: 47 + 38 ≈ 50 + 40 = 90, close to 85, so it looks right.
Why start from the ones column?
Because a carry moves from a smaller place to a larger one. Starting on the left would mean fixing earlier columns after the fact.