Line up the columns. Add ones first, then tens.
Keep your columns straight!
Add the ones column first, then the tens column.
23
+ 34
+ 42
45
+ 21
+ 33
One of these is wrong. Find it, explain the error, and fix it.
23
+ 45
68
✓ or ✗?
If wrong, fix:
37
+ 42
69
✓ or ✗?
If wrong, fix:
Create Your Own
Make a column addition problem where the answer is 87. Write it and solve it.
+
87