Subject: Grade 4 Math Help !!!
Name: Kim
Who are you: Parent

We're having a hard time with this question.......

Write the digits 1 to 9 on index cards, arrange the cards to form three 3-digit numbers (using each card only ONCE).
The third number is the sum of the first two numbers
** how many different ways can you do this?? **
Apparently there are 320 different solutions but we can't even come up with ONE !! HELP !!

Kim,

Well it would be hard for you to find all of the solutions and it probably needs some observations on the fact that you have 5 odd digits and 4 even digits and on whether or not you have to consider carries for a solution. However, let me give you an example and indicate how you may get other solutions from it.

324
657
–––
981

Now you can easily switch numbers around; for example

327
654
___
981

or

243
576
___
819

and so on. How many can you find this way?

Good luck,

Penny