4300-43*99=
43*100-43*99=
43(100-99)=43*1=43
999*156+156=
156*(999+1)=
156*1000=156000
128*32+872*31-1000*31=
128*32+31*(872-1000)=
128*32-31*128=
128*(32-31)=128*1=128
999*999-999*989-9990=
999*999-999*989-999*10=999*(999-989-10)=
999*0=0
728*359-638*359
+641*90=
359*(728-638)+641*90=
359*90+641*90=
90*(359+641)=90*1000=
90000