(3,09:1/40-32,3:17\50)•1/4+0,069•1/3

(309/5*2-19*5)*1/4+69/1000*1/3

(618/5-95)*1/4+23/1000

143/5*1/4+23/1000

143/20+23/1000

7173/1000=7 173/1000~7,173