how do you teach division

[greenwichgroove]

Dd1 is sen and behind, I went through her test paper and division is a huge problem. School have asked me to help in holidays with her.

How do I move on from division using blocks to mental bearing in mind she has times table issues.

Dividion is taught by chunking nowadays - which is repeated subtraction. There are You Tube videos that clearly show chunking.

Many schools do not use chunking though as it's a rubbish method for all but small numbers (speaking as a Head of Maths!), check what method your school uses before trying something out.

Go back to basics and work on the times tables/division facts, without these doing anything else is really a waste of time.

We teach division by saying, 'how many 3s in 24 or how many 17s in 345 etc.' the children count up. For bigger numbers they are are encouraged to count up in groups of 10 or 20 or 100 depending on the size of the numbers.

No indication of age or stage of child, so unsure of what sort of level you are needing help with, but will do my best.
Division is broadly taught using two methods: sharing (there are 15 sweets and they need to be shared between 5 children - best modelled using blocks) and grouping (also called chunking)(there are 25 eggs to go into boxes holding 6 eggs each, so how many boxes are needed), often modelled using a blank number line, but it leads into the 'traditional' layout. Children need to know and understand both concepts.
Sharing only works effectively for small numbers, but is an important step to go through. Does your DD1 have this concept? If not, practise using physical objects. Only when she can manipulate the objects should she try to write the number sentence. In the meantime, you can write it for her to show how it looks.
Grouping is a more efficient method with larger numbers, but is hard for anybody to teach who is not themselves confident with it. I would suggest asking for more guidance from school how you can best help.
For either method to work well your DD1 will need a good grasp of times tables, so it may well be that the problem is here rather than with the concept of division.
In my experience, if a child has a good grasp of tables, s/he picks up both sharing and chunking very easily as the concepts are very easy. It is perfectly possible for SEN children to reach at least Level 4 in Y6 using only chunking. The problems arise when children are moved on to formal or abstract methods before they understand the basics.

You might find this helpful

www.lancsngfl.ac.uk/curriculum/math/download/file/Division%20-%20mental%20progression%20final.pdf

I'm not a primary maths teacher.

A different approach that we have used with our second child and two neighbouring children in our community (they are all aged 5 and 6) has been to eschew conceptual understanding in all but the most simplistic division/sharing ways (through regular home-0based acitivities like sharing a packet of biscuits between the five children) and go straight to written division problems, an hour a day for a week got them to double digit division with ease - inspired by 1960's Ohio educational experiment available on UTube.
They will learn dividion facts for recall as they learn their times tables over the next few months -we are seeing factual recall as a different skill to written division in our maths work with children here, divdion follows from understanding the place value of numbers, not from times tables, and is therefore easier to learn.