Priscilla,

The problem here is simple,
it's the presentation which is hard.
Let me walk you through it.

ELLIE HAS 12 BOOKS. SHE GIVES AWAY 3 BOOKS.

These are the facts you need to use

ELLIE HAS _LEFT.

This is the answer you will get. You (or your child)
will probably solve it mentally; the rest of the problem
is to show its' understood.

_ - _ = _

Fill in the subtraction problem you actually solved here.

_- _ = _

Fill in the other subtraction problem using the same numbers
(if one was a-b = c, the other will be a-c=b)

_+_ = _

I've corrected a typo here; fill in one of the two addition problems you can make from the same numbers (eg, c+b=a)

_ + _ = _

And fill in the other one - use the fact that addition is commutative, that is, the order does not matter.

Good Hunting!
RD