Respuesta :

80.5 is the answer to this problem.

644 = 400 + 200 + 40 + 4

400 : 8 = 50
200 : 8 = 25
40 : 8 = 5
4 : 8 = 1 : 2 = 0.5

therefore

644 : 8 = 50 + 25 + 5 + 0.5 = 80.5