Question

42:23+{78-3[(15+7•5):5]-3•7}

Answer 1

42:23+{78-3[(15+35):5]-3•7 }                                                              42+23+ { 78-3(50+5)-3•7 }                                                            42+23+[78-3 •55-3 •7 ]                                                                      42+23+[ 78-165•21]                                                                               42+23+(78-3465)   42+23+3387                                                                                               3452