Respuesta :

107 - 98 = 9
98 - 90 = 8
90 - 83 = 7
83 - 77 = 6
u seeing a pattern here ?
77 - x = 5....77 - 5 = x...72 = x

check..
77 - 72 = 5
72 - 68 = 4
68 - 65 = 3

so ur missing number = 72

it is seventy-two . because
the pattern is -9,-8,-7,-6 etc.