Răspuns:
sunt aplicate proprietatil inmultirii
a) 56 ×23=1288
23×56=1288
56 ×23=23×56
inmultire comutativa
b) (56×23)×7=1288·7=9016
56 ×(23 × 7)=56·161=9016
(56×23)×7=56 ×(23 × 7)
inmultire asociativa
c) 42×(6+9)=42·6+42·9=252+378=630
42×15=630
42×(6+9) = 42×15
inmultire distributiva