[tex]\it 68\cdot43 = 2924\\ \\ \rule{0.2}{0.2}\ \ \ \ 68\cdot\\ \rule{0.2}{0.2}\ \ \ \ 43\\ \rule{30}{0.6}\\ \rule{0.2}{0.2}\ \ \ 204\\\rule{0.2}{0.2}\ 272\\ \rule{29}{0.5}\\ \rule{0.2}{0.2}\ 2924\\ \\ \\ 72\cdot43 =3096\\ \\ 15\cdot43 = 645[/tex]
[tex]\it \rule{0.2}{0.2}\ \ \ \ 72\cdot\\ \rule{0.2}{0.2}\ \ \ \ 43\\ \rule{30}{0.6}\\ \rule{0.2}{0.2}\ \ \ 216\\\rule{0.2}{0.2}\ 288\\ \rule{29}{0.5}\\ \rule{0.2}{0.2}\ 3096[/tex]
[tex]\it 39\cdot43=1677\\ \\ \rule{0.2}{0.2}\ \ \ \ 39\cdot\\ \rule{0.2}{0.2}\ \ \ \ 43\\ \rule{30}{0.6}\\ \rule{0.2}{0.2}\ \ \ 117\\\rule{0.2}{0.2}\ 156\\ \rule{29}{0.5}\\ \rule{0.2}{0.2}\ 1677[/tex]
