Wykonajmy mnożenie pisemne.

a)

$\begin{array}{rr}73& \\ \underline{\cdot 21}& \\ 73& \leftarrow 73\cdot 1\\ \underline{+146}& \leftarrow 73\cdot 2\\ 1533& \end{array}$

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$\begin{array}{rr}48& \\ \underline{\cdot 23}& \\ 144& \leftarrow 48\cdot 3\\ \underline{+96}& \leftarrow 48\cdot 2\\ 1104& \end{array}$

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$\begin{array}{rr}235& \\ \underline{\cdot 17}& \\ 1645& \leftarrow 235\cdot 7\\ \underline{+235}& \leftarrow 235\cdot 1\\ 3995& \end{array}$

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$\begin{array}{rr}537& \\ \underline{\cdot 15}& \\ 2685& \leftarrow 537\cdot 5\\ \underline{+537}& \leftarrow 537\cdot 1\\ 8055& \end{array}$

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b)

$\begin{array}{rr}854& \\ \underline{\cdot 45}& \\ 4270& \leftarrow 854\cdot 5\\ \underline{+3416}& \leftarrow 854\cdot 4\\ 38430& \end{array}$

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$\begin{array}{rr}345& \\ \underline{\cdot 240}& \\ 1380& \\ \underline{+690}& \\ 82800& \end{array}$

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$\begin{array}{rr}27480& \\ \underline{\cdot 280}& \\ 21984& \\ \underline{+5496}& \\ 7694400& \end{array}$