
There are 30 kids in the cafeteria and 23 more kids come in for lunch. How many kids are in the cafeteria now?
She began using manipulatives at first, but then decided to use her paper instead. She first wrote out 30 - 23. Then she drew a line between the 3 and the 2 and wrote "50" underneath it, and a line between the 0 and the 3 and wrote "3" underneath it. Then she added the "50" and the "3" to get 53. This really showed how she was able to break the number apart into tens and ones and add them together separately.
When she wrote it out on her paper, it looked something like this:

In this way, she grouped her groups of tens together (3 + 2 to make 5, which she knew represented 50) and her ones together (0 + 3).
Another strategy she could have used would be to use manipulatives to demonstrate the addition by having one color (red) representing tens and another color (blue) representing ones. Then she could add the red manipulatives together and the blue manipulatives together to represent each place value of the answer : 53.
She could also use a counting technique of drawing out ten sticks on her paper and then adding them together. She could then draw out ones on her paper and add those together. Then she could add the two answers together.
Both of these methods are similar to the method she utilized, but are just slightly different ways of approaching it.