Column addition and subtraction
Write numbers in columns and add or subtract one column at a time: carry a ten to the next column, exchange from the column next door, and check your answer.
- UK: Year 2
- France: grade 1
- Germany: grade 1
- Iran: grade 2
- Afghanistan: grade 2
- Syria: grade 2
- Palestine: grade 2
- Ukraine: grade 2
- Russia: grade 2
Guide
When numbers get bigger, we use the column method (vertical layout) for addition and subtraction. Write the numbers one under the other so that ones are under ones, tens under tens and hundreds under hundreds. This is what place value columns are for.
Always start with the ones column on the right, and work left one column at a time. Each box holds just one digit.
If a column adds up to 10 or more, like 8 + 7 = 15, write the 5 in that column and carry the 1 ten to the next column: write a small 1 under the answer line. Add it in when you do that column.
In subtraction, if the top digit is smaller than the bottom digit, exchange one from the column on the left (exchanging (borrowing) in subtraction): tap the top digit of that column. It goes down by one, gets crossed out, and its new value is written above it. Your column gets 10 more.
To check a subtraction, add the difference to the number you took away. If you get back the first number, your answer is right.
Every digit you get right turns green. If a digit isn't right yet, it gets a dotted border so you can work it out again. If you get stuck, press "Show me this column".