Explicație pas cu pas:
5*(134+537)=5*671=3355
5*134+5*537=670+2685=3355
21*(98+345)=21*443=9303
21*98+21*345=2058+7245=9303
3*(790-99)=3*691=2073
3*790-3*99=2370-297=2073
56*(76+98)=56*174=9744
56*76+56*98=4256+5488=9744
4*(728-179)=4*549=2196
4*728-4*179=2912-716=2196
43*(157+472)=43*629=27047
43*157+43*472=6751+20296=27047