Addition with regrouping

Type an addition like `352 + 179`, or several numbers at once, like `1,234 + 56 + 7`. The answer appears with the sum drawn in columns and every carry written above the column it goes to, and each column is explained underneath.

Decimals work too, with the points lined up: `12.5 + 3.75`. For taking away, use subtraction with regrouping.

Line the numbers up by place value, ones under ones, and add from the right. When a column adds up to 10 or more, it's too big for one digit. Write the ones digit of the total, and regroup the ten as 1 in the next column, where it's added with the others. That 1 is the carry.

In `352 + 179`, the ones are 2 + 9 = 11: write 1 and carry 1 to the tens. The tens are 5 + 7 + 1 = 13: write 3, carry 1 to the hundreds. The hundreds are 3 + 1 + 1 = 5. The answer is 531.

Adding three or more numbers works the same way, and a column can carry more than 1. Nine 9s in the ones make 81, so you'd write 1 and carry 8.

Each place is worth ten of the place to its right. Eleven ones are the same as one ten and one one, so writing 1 and carrying 1 just moves the ten to the column that counts tens. Nothing is added or lost; the number is only regrouped into the places where it belongs. The place value chart shows the same idea for any number.