Răspuns :
19)324978+87234=412212
846157:13=65089
412212-65089=347123
20)409235-264196=145039
2304•76=175104
145039+175104=320143
846157:13=65089
412212-65089=347123
20)409235-264196=145039
2304•76=175104
145039+175104=320143