@PicturesFoIder Starting at the 2nd number in each, 7+8 is 15 so 5 is the right most digit of the result and 1 is added to the lefts sum. 2+4 is 6, plus 1 from the 15 that's 7. Answer is 75.
Alternatively, 27 is 2 more than 25. 48 is 2 less than 50. Negating each other so 25 plus 50 is 75.