Răspuns:
(4209+2103)×6=6312×6=37862
urmatorul supunct =4209×6-2103×6=
25.254-12618=12636
cpl succes
(a+b)×c=(4209+2103)×6
(a+b)×c=6312×6
(a+b)×c=37872
ac-bc=c×(a-b)
ac-bc=6×(4209-2103)
ac-bc=6×2106
ac-bc=12636
