How to help dcs understand division facts?

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My dcs just about 'get' that eg 2 x 9 = 18, so if you read it backwards as a division, it works.

How can I help them get 18 divided by 2 = 9 as well. There must be a triangle method or something.

tia!

Because 2 x 9 = 18 just the same as 9 x 2 = 18. Get 18 blocks and then split them into nine piles of two; and then into two piles of nine.

Make an array with 2 rows of 9, agree that there are 18, turn the array round so you have 9 rows of 2, still 18, divide the array into 2 rows, how many in each (9), divide the array into 9 rows, how many in each (2).I use a very large egg tray as mine!

There's a nice explanation on the apex math website. They also sell some good value multiplication/division workbooks.

egg trays or bun tins are great ways to give a practical demonstration.
division/multiplication arrays

division games

www.scribd.com/doc/25057713/Primary-Maths-Newsletter-Spring-2010 page 13

sweets - get 18 sweets and split them between two people - voila - you have 9 sweets.

Show her that is the same as starting with no sweets and giving 8 to each of 2 people - then count up how many you have.

Somehow sweets puts it into a context they understand (and you can give them one as reward and then do the whole calculation again with less sweets :)).

I like the triangle method, say:
-----18
----9 x 2
cover up the 'answer'. so cover up 2, and you get 18 over 9 i.e. 18 divided by 9, or cover up 9, and you get 18 divided by 2. or cover up 18 and you get 9 x 2.

you can also do this with scientific formulae - they got me through my exams! :) e.g.
----distance
--speed x time

Thanks everyone!

Once you've demonstrated using some of the techniques above, getting them to write "sum families" helps with practising. eg:

2x9=18
what other sums belong in this "family"
then show them
9x2=18
18 divided by 2 = 9
18 divided by 9 = 2

Then get them to try this with other sums.

You can even make cut out people holding hands (ie fold a sheet of paper into 4 as a zigzag and draw gingerbread boy/girl style person with hands that touch the folded sides. Cut out but not along the folds where the hands meet. You then get 4 people holding hands) and write one of each of the 4 family sums on each person.

Another way is to make "happy families" cards with the 4 sums in a family written on a card each. Do this for about 8 to 12 different "families" and then play happy families by the normal rules

www.safaripals.com/rules/happy-families.htm

that's a really cool idea!

www.coolmath4kids.com/