My strategy is to start with the hundreds colomn and make 900 while trying to use the biggest numbers possible so that when i want to make 100 it will be easier to make it with smaller numbers. Then i will try and make a number as close to ten in the one and ten colomns so then that will be quite close to one thousand.
The closest I've got was two away probably becuase i got quite small numbers which made it easier
My strategy won't always work because if you get really big numbers then it is harder to make 900 and 100 so you will probably end up getting a higher number than 1000.
My strategy worked best when I got smaller numbers because then you can make a bunch of smaller number and it will likely add up to 100.