When you subtract in columns, you work column by column from right to left.
The ones go under the ones, the tens under the tens.
Here is how you do it:
1. First subtract the ones.
2. If the top digit is too small, you take 1 from the next place value.
3. Then subtract the tens.
Tip: When you regroup, you take one ten and note it down next to it.
The numbers filled in show the solution.
Example
- 24
- 34
For parents
What does this exercise practice?
This exercise trains place-value understanding and regrouping when subtracting.
Common pitfalls
Children often forget to note the regrouping or subtract the smaller digit from the bigger one. Always write the carry down!
How to practice at home
When you work out the change while shopping, you can check the result in columns.
Related: Written +, Calculation