３位数×２位数（型分け）

３位数×２位数のかけ算も２位数×２位数の計算に、部分積が３位数×１位数と桁が増える以外に、新たな計算手続きが必要になることはありません。
但し、部分積の和が５位数になることもあるので、加法の計算力が問われる場面でもあります。
０のある型の計算の簡便法（０の省略／計算の工夫）は、×３位数完成後行いますが、学習塾や学校によっては、この段階から指導する場合もあります。

３位数×２位数の型分け

［１］
\setstretch{0.5} \begin{array}{rr} & \square\square\square \\ \times & \square \square \\ \hline & \square\square\square \\ & \square\square\square\hspace*{0.8em} \\ \hline & \square\square\square\square \\ \end{array} \begin{array}{rr} & 123 \\ \times & 32 \\ \hline \end{array} \begin{array}{rr} & 231 \\ \times & 12 \\ \hline \end{array} \begin{array}{rr} & 433 \\ \times & 22 \\ \hline \end{array}
［２］
\setstretch{0.5} \begin{array}{rr} & \square\square\square \\ \times & \square \square \\ \hline & \square\square\square\square \\ & \square\square\square\hspace*{0.8em} \\ \hline & \square\square\square\square \\ \end{array} \begin{array}{rr} & 234 \\ \times & 26 \\ \hline \end{array} \begin{array}{rr} & 245 \\ \times & 47 \\ \hline \end{array} \begin{array}{rr} & 187 \\ \times & 16 \\ \hline \end{array}
［３］
\setstretch{0.5} \begin{array}{rr} & \square\square\square \\ \times & \square \square \\ \hline & \square\square\square\square \\ & \square\square\square\hspace*{0.8em} \\ \hline & \square\square\square\square\square \\ \end{array} \begin{array}{rr} & 836 \\ \times & 17 \\ \hline \end{array} \begin{array}{rr} & 694 \\ \times & 18 \\ \hline \end{array} \begin{array}{rr} & 898 \\ \times & 19 \\ \hline \end{array}
［４］
\setstretch{0.5} \begin{array}{rr} & \square\square\square \\ \times & \square \square \\ \hline & \square\square\square \\ & \square\square\square\square\hspace*{0.8em} \\ \hline & \square\square\square\square\square \\ \end{array} \begin{array}{rr} & 426 \\ \times & 72 \\ \hline \end{array} \begin{array}{rr} & 694 \\ \times & 91 \\ \hline \end{array} \begin{array}{rr} & 461 \\ \times & 32 \\ \hline \end{array}
［５］
\setstretch{0.5} \begin{array}{rr} & \square\square\square \\ \times & \square \square \\ \hline & \square\square\square\square \\ & \square\square\square\square\hspace*{0.8em} \\ \hline & \square\square\square\square\square \\ \end{array} \begin{array}{rr} & 732 \\ \times & 53 \\ \hline \end{array} \begin{array}{rr} & 293 \\ \times & 66 \\ \hline \end{array} \begin{array}{rr} & 324 \\ \times & 78 \\ \hline \end{array}
［６］
\setstretch{0.5} \begin{array}{rr} & \square\square\square \\ \times & \square \hspace*{0.13em}0\hspace*{0.13em} \\ \hline & \hspace*{0.13em}0\hspace*{0.13em}\hspace*{0.13em}0\hspace*{0.13em}\hspace*{0.13em}0\hspace*{0.13em} \\ & \square\square\square\hspace*{0.8em} \\ \hline & \square\square\square\hspace*{0.14em}0\hspace*{0.14em} \\ \end{array} \begin{array}{rr} & 213 \\ \times & 30 \\ \hline \end{array} \begin{array}{rr} & 324 \\ \times & 30 \\ \hline \end{array} \begin{array}{rr} & 123 \\ \times & 60 \\ \hline \end{array}
［７］
\setstretch{0.5} \begin{array}{rr} & \square\square\square \\ \times & \square\hspace*{0.13em}0\hspace*{0.13em} \\ \hline & \hspace*{0.13em}0\hspace*{0.13em}\hspace*{0.13em}0\hspace*{0.13em}\hspace*{0.13em}0\hspace*{0.13em} \\ & \square\square\square\square\hspace*{0.8em} \\ \hline & \square\square\square\square\hspace*{0.14em}0\hspace*{0.14em} \\ \end{array} \begin{array}{rr} & 921 \\ \times & 40 \\ \hline \end{array} \begin{array}{rr} & 438 \\ \times & 80 \\ \hline \end{array} \begin{array}{rr} & 863 \\ \times & 40 \\ \hline \end{array}
［８］
\setstretch{0.5} \begin{array}{rr} & \square\square\hspace*{0.13em}0\hspace*{0.13em} \\ \times & \square\hspace*{0.13em}0\hspace*{0.13em} \\ \hline & \hspace*{0.13em}0\hspace*{0.13em}\hspace*{0.13em}0\hspace*{0.13em}\hspace*{0.13em}0\hspace*{0.13em} \\ & \square\square\hspace*{0.13em}0\hspace*{0.13em}\hspace*{0.8em} \\ \hline & \square\square\hspace*{0.14em}0\hspace*{0.14em} \hspace*{0.14em}0\hspace*{0.14em} \\ & (\square\square\square\hspace*{0.14em}0\hspace*{0.14em} \hspace*{0.14em}0\hspace*{0.14em}) \\ \end{array} \begin{array}{rr} & 430 \\ \times & 20 \\ \hline \end{array} \begin{array}{rr} & 120 \\ \times & 30 \\ \hline \end{array} \begin{array}{rr} & 240 \\ \times & 40 \\ \hline \end{array}
［９］
\setstretch{0.5} \begin{array}{rr} & \square\hspace*{0.13em}0\hspace*{0.13em}\hspace*{0.13em}0\hspace*{0.13em} \\ \times & \square\hspace*{0.13em}0\hspace*{0.13em} \\ \hline & \hspace*{0.13em}0\hspace*{0.13em}\hspace*{0.13em}0\hspace*{0.13em}\hspace*{0.13em}0\hspace*{0.13em} \\ & \square\hspace*{0.13em}0\hspace*{0.13em}\hspace*{0.13em}0\hspace*{0.13em}\hspace*{0.8em} \\ \hline & \square\hspace*{0.14em}0\hspace*{0.14em}\hspace*{0.14em}0\hspace*{0.14em}\hspace*{0.14em}0\hspace*{0.14em} \\ & (\square\square\hspace*{0.14em}0\hspace*{0.14em}\hspace*{0.14em}0\hspace*{0.14em}\hspace*{0.14em}0\hspace*{0.14em}) \\ \end{array} \begin{array}{rr} & 200 \\ \times & 30 \\ \hline \end{array} \begin{array}{rr} & 800 \\ \times & 70 \\ \hline \end{array} \begin{array}{rr} & 300 \\ \times & 20 \\ \hline \end{array}