分数の掛け算/帯分数/小学校6年生相当の算数/一般常識クイズ一問一答問題まとめ
問題
①\( \begin{array}{l} 1\dfrac{4}{5}\times 10 \end{array} \)
②\( \begin{array}{l} \begin{aligned}2\dfrac{1}{3}\times \dfrac{3}{5}\end{aligned} \end{array} \)
③\( \begin{array}{l} 4\dfrac{1}{2}\times 1\dfrac{2}{3} \end{array} \)
④\( \begin{array}{l} 3\dfrac{4}{5}\times 2\dfrac{1}{3} \end{array} \)
解法/ポイント
帯分数は仮分数に直してから計算しましょう。
解答
①\( \begin{array}{l} 1\dfrac{4}{5}\times 10=\dfrac{9}{5}\times 10=18 \end{array} \)
②\( \begin{array}{l} \begin{aligned}2\dfrac{1}{3}\times \dfrac{3}{5}=\dfrac{7}{3}\times \dfrac{3}{5}\ =\dfrac{7}{5}\ =1\dfrac{2}{5}\end{aligned} \end{array} \)
③\( \begin{array}{l} 4\dfrac{1}{2}\times 1\dfrac{2}{3}=\dfrac{9}{2}\times \dfrac{5}{3}=\dfrac{15}{2}=7\dfrac{1}{2} \end{array} \)
④\( \begin{array}{l} 3\dfrac{4}{5}\times 2\dfrac{1}{3}=\dfrac{19}{5}\times \dfrac{7}{3}=\dfrac{133}{15}=8\dfrac{13}{15} \end{array} \)