Sequencing numbers/letters that are NOT cosecutive

[Guest guest]

I have a question on how to sequencing numbers/letters when they are not

conescutive numbers/letters.

Let me explain...

If I give my daughter letters A through G(A, B,C,D,E,F,G) and ask her to put

them in order or sequence them, she will do it.

If I give her letters A, D and F and ask her to put them in order or sequence

them, she will NOT(can't)do it.

Same is the case with numbers.

How do I go about teaching that? using a number line of sorts?What do I do for

letters? is it even relevant for letters?