GMT -5 9:00 YOU NEED TO ADD 1 hour thats mean 10:00 ITS THE ORIGINAL TIME because they got not -4 but -5
GMT -4 10:00 YOU NEED TO ADD +1 hour thats mean 11:00 ( because of daylight saving)
GMT -3 11.00 YOU NEED TO ADD +1 hour thats mean 12:00 ( because of daylight saving)
GMT -2 12.00 YOU NEED TO ADD +1 hour thats mean 13:00 ( because of daylight saving)
GMT -1 13.00 YOU NEED TO ADD +1 hour thats mean 14:00 ( because of daylight saving)
GMT 0 14.00 YOU NEED TO ADD +1 hour thats mean 15:00 ( because of daylight saving)
GMT +1 15.00 YOU NEED TO ADD +1 hour thats mean 16:00 ( because of daylight saving)
GMT +2 16.00 YOU NEED TO ADD +1 hour thats mean 17:00 ( because of daylight saving)