a, 54 : 9 + 15 . 2
= 6 + 30 = 36
b, $\frac{35 . 53 - 18}{35 + 53 . 34}$
= $\frac{34 . 53 - 18 + 53}{35 + 5 3 . 34}$ = $\frac{34 . 53 + 35}{35 + 53 . 34}$ = 1
c, ( 456 . 11 + 912 ) .37
= ( 456 . 10 + 456 + 912 ) . 37
= (4560 + 456 + 912) . 37
= 5928 . 37 = 219336