The number halfway between them is 600.
750
650
The halfway point between 700 and 800 is (700 + 800) ÷ 2 = 750
550 is halfway between 500 and 600
252 = 625
700
525 is halfway between 350 and 700.
700
700
600 as it is 49 away from 600 but is 51 away from 700
850.