Forwards Add Backwards Lamees E

Please take a look at my solution to this challenge, uploaded. I took a rather algebraic approach, blending place value and equations to create a set of conditions that must be met to result in my final 10 solutions to find all the totals between 700 and 800. At every step, I clearly formatted my reasoning and explained why it cannot be any other solution, similar to UKMT JMO’s proof formatting. Thank you, Lamees Ede.