Some students have difficulty copying and aligning problems, so I have them write the numbers in a window.
The student adds the ones column and shows the answer with number cards. The student can see that 2 digits should not be place in one box and carries the one to the tens column
like this...
The student then adds the tens column and shows the answer with a a number card again.
The student then prints the answer.
This tactile activity has been very helpful with my differential learner who gets very distracted using blocks and manipulatives.