1.次の計算をしなさい。
(1)\(\displaystyle \frac{1}{3}×\frac{4}{7}\)
\(\displaystyle \frac{4}{21}\)
(2)\(\displaystyle \frac{5}{9}×\frac{3}{8}\)
\(\displaystyle \frac{5}{24}\)
(3)\(\displaystyle \frac{7}{12}×\frac{8}{21}\)
\(\displaystyle \frac{2}{9}\)
(4)\(\displaystyle \frac{5}{24}×\frac{12}{35}\)
\(\displaystyle \frac{1}{14}\)
(5)\(\displaystyle 1\frac{1}{2}×\frac{3}{5}\)
\(\displaystyle \frac{9}{10}\)
(6)\(\displaystyle 2\frac{1}{3}×1\frac{3}{7}\)
\(\displaystyle \frac{10}{3}\)
(7)\(\displaystyle \frac{2}{5}×\frac{4}{3}\)
\(\displaystyle \frac{8}{15}\)
(8)\(\displaystyle \frac{2}{9}×\frac{1}{3}\)
\(\displaystyle \frac{2}{27}\)
(9)\(\displaystyle \frac{1}{3}×\frac{7}{6}\)
\(\displaystyle \frac{7}{18}\)
(10)\(\displaystyle 1\frac{1}{5}×2\frac{2}{7}\)
\(\displaystyle \frac{96}{35}\)
(11)\(\displaystyle 3\frac{1}{2}×1\frac{2}{5}\)
\(\displaystyle \frac{49}{10}\)
(12)\(\displaystyle 1\frac{1}{6}×1\frac{2}{9}\)
\(\displaystyle \frac{77}{54}\)
(13)\(\displaystyle \frac{3}{28}×\frac{7}{9}\)
\(\displaystyle \frac{1}{12}\)
(14)\(\displaystyle \frac{2}{8}×\frac{3}{9}\)
\(\displaystyle \frac{1}{12}\)
(15)\(\displaystyle \frac{9}{14}×\frac{2}{3}\)
\(\displaystyle \frac{3}{7}\)
(16)\(\displaystyle \frac{3}{5}×\frac{5}{6}×\frac{5}{7}\)
\(\displaystyle \frac{5}{14}\)
(17)\(\displaystyle \frac{5}{6}×\frac{9}{10}×\frac{1}{7}\)
\(\displaystyle \frac{3}{28}\)
(18)\(\displaystyle \frac{1}{5}×\frac{3}{8}×\frac{4}{9}\)
\(\displaystyle \frac{1}{30}\)
(19)\(\displaystyle \frac{1}{6}×\frac{3}{7}×\frac{7}{8}\)
\(\displaystyle \frac{1}{16}\)
(20)\(\displaystyle 1\frac{1}{4}×\frac{2}{3}\)
\(\displaystyle \frac{5}{6}\)
(21)\(\displaystyle 1\frac{3}{8}×\frac{4}{5}\)
\(\displaystyle \frac{11}{10}\)
(22)\(\displaystyle 5\frac{1}{4}×1\frac{7}{9}\)
\(\displaystyle \frac{28}{3}\)
(23)\(\displaystyle 6×\frac{5}{9}×\frac{2}{3}\)
\(\displaystyle \frac{20}{9}\)
(24)\(\displaystyle 2\frac{2}{5}×1\frac{1}{6}\)
\(\displaystyle \frac{14}{5}\)
(25)\(\displaystyle 1\frac{1}{3}×2\frac{5}{2}\)
\(\displaystyle 6\)
(26)\(\displaystyle \frac{2}{7}×1\frac{2}{5}\)
\(\displaystyle \frac{2}{5}\)
(27)\(\displaystyle \frac{8}{9}×1\frac{3}{8}\)
\(\displaystyle \frac{11}{9}\)
(28)\(\displaystyle \frac{1}{5}×\frac{3}{8}×\frac{4}{9}\)
\(\displaystyle \frac{1}{30}\)
(29)\(\displaystyle 1\frac{1}{3}×1\frac{1}{5}\)
\(\displaystyle \frac{8}{5}\)
(30)\(\displaystyle \frac{2}{9}×2×\frac{3}{8}\)
\(\displaystyle \frac{1}{6}\)
2.次の問いに答えなさい。
(1)1dℓで\(\displaystyle \frac{4}{5}\)m\(^2\)の壁を塗れるペンキがある。このペンキが\(\displaystyle \frac{12}{7}\)dℓあるとき、何m\(^2\)の壁が塗れるか答えなさい。
\(\displaystyle \frac{4}{5}×\frac{12}{7}=\frac{48}{35}\)
【答】\(\displaystyle \frac{48}{35}m^2\)
(2)1mで\(\displaystyle 1\frac{6}{7}\)kgの棒がある。この棒が\(\displaystyle 2\frac{3}{8}\)あるとき、重さは何kgになるか答えなさい。
\(\displaystyle 1\frac{6}{7}×2\frac{3}{8}=\frac{247}{56}\)
【答】\(\displaystyle \frac{247}{56}kg\)
(3)1mで\(\displaystyle \frac{8}{9}\)kgのパイプがある。このパイプが\(\displaystyle \frac{21}{16}\)mあるとき、パイプの重さは何kgになるか答えなさい。
\(\displaystyle \frac{8}{9}×\frac{21}{16}=\frac{7}{6}\)
【答】\(\displaystyle \frac{7}{6}kg\)
(4)1ℓで\(\displaystyle 1\frac{5}{7}\)kgの小豆がある。この小豆が\(\displaystyle 3\frac{4}{15}\)ℓあるとき、重さは何kgになるか答えなさい。
\(\displaystyle 1\frac{5}{7}×3\frac{4}{15}=\frac{28}{5}\)
【答】\(\displaystyle \frac{28}{5}kg\)
(5)底辺が\(\displaystyle 1\frac{9}{16}\)cm、高さが\(\displaystyle 2\frac{2}{15}\)cmの平行四辺形の面積は何cm\(^2\)になるか答えなさい。
\(\displaystyle 1\frac{9}{16}×2\frac{2}{15}=\frac{10}{3}\)
【答】\(\displaystyle \frac{10}{3}cm^2\)
(6)縦が\(\displaystyle 1\frac{5}{8}\)cm、横が\(\displaystyle 2\frac{4}{13}\)cmの長方形の面積は何cm\(^2\)になるか答えなさい。
\(\displaystyle 1\frac{5}{8}×2\frac{4}{13}=\frac{15}{4}\)
【答】\(\displaystyle \frac{15}{4}cm^2\)
(7)1ℓのガソリンで\(\displaystyle 8\frac{4}{7}\)km走るバイクがある。\(\displaystyle 5\frac{2}{15}\)ℓのガソリンで、何km走ることができるか答えなさい。
\(\displaystyle 8\frac{4}{7}×5\frac{2}{15}=44\)
【答】\(\displaystyle 44km\)
(8)縦が\(\displaystyle \frac{2}{3}\)m、横が\(\displaystyle \frac{3}{5}\)m、高さが\(\displaystyle \frac{7}{8}\)mの直方体の体積を求めなさい。
\(\displaystyle \frac{2}{3}×\frac{3}{5}×\frac{7}{8}=\frac{7}{20}\)
【答】\(\displaystyle \frac{7}{20}m^3\)
3.次の計算をしなさい。
(1)\(\displaystyle \left(\frac{2}{5}+\frac{3}{10}\right)×10\)
\(\displaystyle 7\)
(2)\(\displaystyle \left(\frac{7}{8}-\frac{3}{4}\right)×8\)
\(\displaystyle 1\)
(3)\(\displaystyle 8×\left(\frac{3}{4}+\frac{5}{2}\right)\)
\(\displaystyle 26\)
(4)\(\displaystyle 9×\left(\frac{2}{3}-\frac{4}{9}\right)\)
\(\displaystyle 2\)
(5)\(\displaystyle \frac{5}{14}×12+\frac{9}{14}×12\)
\(\displaystyle 12\)
(6)\(\displaystyle \frac{17}{10}×15-\frac{7}{10}×15\)
\(\displaystyle 15\)
(7)\(\displaystyle 8×\frac{7}{11}+8×\frac{4}{11}\)
\(\displaystyle 8\)
(8)\(\displaystyle 9×\frac{9}{7}-\frac{2}{7}×9\)
\(\displaystyle 9\)