Find the autocorrelation for lag 1, lag 2 and lag 3 by using hand calculations i.e. r1,r2,r3

(t ,Y_t):

(1 ,123) (2,130), (3, 125) (4, 138) (5, 145) (6, 142) (7, 141) (8, 146), (9, 147), (10, 157), (11, 150), (12, 160)