Long Division. There are different methods for dividing multi-digit numbers (long division). One way is a combination of estimation/ trial and error and multiplication. There is also a commonly used algorithmic method that is well explained and illustrated here at mathisfun.com.
If a child is really confused about decimals, converting decimal numnbers into money is a great way to make things clearer. For example: a child may be asked to say how much bigger 1.3 is than 0.9. If they convert these decimals into money (£1.30 and 90p) they may find that they can do this calculation very quickly in their head, getting the answer 40p which they convert back into the decimal, 0.4. Demonstrating that money maths depends on decimal understanding is also an easy way to prove that decimals are actually useful in real life!