Puzzle 33: Nine Box Addition

Put the digits 1 through 9, each used once, in the boxes to make the question true.
There are multiple solutions. Find more than one solutions to see the patterns.
Extension: Look at the patterns, why can you switch the digits and can still find a solution? Why the answer is divisible by nine?
There are multiple solutions. Find more than one solutions to see the patterns.
Extension: Look at the patterns, why can you switch the digits and can still find a solution? Why the answer is divisible by nine?