Sneaky's Daily Did You Know....? - Baffled with Science

Once sum is always the same, whatever the numbers, take any three-figure number in which the first figure is larger than the last - for example 834. Then reverse it, making 438, and subtract the smaller number from the larger, making 396. Finally add that to the same number reversed, in this case 693. The answer is 1089, and will be 1089 whatever the starting number!