Tính:

5 × 8 : 4 = ..........................               = ..........................	4 × 9 + 423 = ........................                    = .........................	25 + 27 + 643 = ....................                        = ....................
18 : 2 : 3 = .......................               = ..........................	4 × 7 - 28 =...........................                   = ..........................	789 – 325 – 33 = ..................                          = ..................