《2025年文墨小学数学口算心算天天练五年级下册人教版》

① $\frac{9}{10} × \frac{9}{10} × \frac{2}{3} =$

答案： $\frac{9}{10} × \frac{2}{3} = \frac{18}{30} = \frac{3}{5}$，$\frac{3}{5} × \frac{9}{10} = \frac{27}{50}$

② $\frac{11}{12} × (1 - \frac{5}{11}) =$

答案： $1 - \frac{5}{11} = \frac{6}{11}$，$\frac{11}{12} × \frac{6}{11} = \frac{66}{132} = \frac{1}{2}$

③ $(\frac{1}{8} - \frac{1}{10}) × 80 =$

答案： $\frac{1}{8} × 80 = 10$，$\frac{1}{10} × 80 = 8$，$10 - 8 = 2$

④ $(10 - \frac{10}{11}) × \frac{11}{12} =$

答案： $10 × \frac{11}{12} = \frac{110}{12}$，$\frac{10}{11} × \frac{11}{12} = \frac{10}{12}$，$\frac{110}{12} - \frac{10}{12} = \frac{100}{12} = \frac{25}{3}$

⑤ $16 × 7 × \frac{9}{14} =$

答案： $7 × \frac{9}{14} = \frac{9}{2}$，$16 × \frac{9}{2} = 72$

⑥ $\frac{8}{15} + \frac{9}{16} + \frac{4}{5} =$

答案： $\frac{4}{5} = \frac{12}{15}$，$\frac{8}{15} + \frac{12}{15} = \frac{20}{15} = \frac{4}{3}$，$\frac{4}{3} + \frac{9}{16} = \frac{64}{48} + \frac{27}{48} = \frac{91}{48}$

⑦ $\frac{9}{28} × \frac{14}{25} × \frac{5}{7} =$

答案： $\frac{9}{28} × \frac{14}{25} = \frac{126}{700} = \frac{9}{50}$，$\frac{9}{50} × \frac{5}{7} = \frac{45}{350} = \frac{9}{70}$

⑧ $54 × (\frac{4}{27} + \frac{5}{9}) =$

答案： $\frac{5}{9} = \frac{15}{27}$，$\frac{4}{27} + \frac{15}{27} = \frac{19}{27}$，$54 × \frac{19}{27} = 38$

⑨ $(\frac{7}{10} + \frac{5}{6}) × 30 =$

答案： $\frac{7}{10} × 30 = 21$，$\frac{5}{6} × 30 = 25$，$21 + 25 = 46$

⑩ $\frac{1}{3} × \frac{1}{3} + 3 =$

答案： $\frac{1}{3} × \frac{1}{3} = \frac{1}{9}$，$\frac{1}{9} + 3 = 3\frac{1}{9} = \frac{28}{9}$

⑪ $\frac{5}{21} × \frac{3}{10} × \frac{7}{10} =$

答案： $\frac{5}{21} × \frac{3}{10} = \frac{15}{210} = \frac{1}{14}$，$\frac{1}{14} × \frac{7}{10} = \frac{7}{140} = \frac{1}{20}$

⑫ $\frac{4}{5} × (5 - \frac{5}{8}) =$

答案： $5 - \frac{5}{8} = \frac{35}{8}$，$\frac{4}{5} × \frac{35}{8} = \frac{140}{40} = \frac{7}{2}$

⑬ $\frac{3}{8} × \frac{4}{5} × \frac{5}{6} =$

答案： $\frac{4}{5} × \frac{5}{6} = \frac{20}{30} = \frac{2}{3}$，$\frac{3}{8} × \frac{2}{3} = \frac{6}{24} = \frac{1}{4}$

⑭ $\frac{5}{7} × (\frac{2}{5} + 11) =$

答案： $\frac{5}{7} × \frac{2}{5} = \frac{10}{35} = \frac{2}{7}$，$\frac{5}{7} × 11 = \frac{55}{7}$，$\frac{2}{7} + \frac{55}{7} = \frac{57}{7}$

⑮ $\frac{1}{2} × \frac{8}{9} - \frac{11}{36} =$

答案： $\frac{1}{2} × \frac{8}{9} = \frac{4}{9} = \frac{16}{36}$，$\frac{16}{36} - \frac{11}{36} = \frac{5}{36}$

⑯ $\frac{1}{4} × \frac{9}{10} × \frac{5}{18} =$

答案： $\frac{9}{10} × \frac{5}{18} = \frac{45}{180} = \frac{1}{4}$，$\frac{1}{4} × \frac{1}{4} = \frac{1}{16}$

⑰ $\frac{8}{15} × \frac{9}{24} + \frac{1}{5} =$

答案： $\frac{8}{15} × \frac{9}{24} = \frac{72}{360} = \frac{1}{5}$，$\frac{1}{5} + \frac{1}{5} = \frac{2}{5}$

⑱ $\frac{2}{3} + \frac{3}{8} × \frac{4}{5} =$

答案： $\frac{3}{8} × \frac{4}{5} = \frac{12}{40} = \frac{3}{10}$，$\frac{2}{3} + \frac{3}{10} = \frac{20}{30} + \frac{9}{30} = \frac{29}{30}$

⑲ $50 × (1 + \frac{1}{5}) =$

答案： $50 × 1 = 50$，$50 × \frac{1}{5} = 10$，$50 + 10 = 60$

⑳ $\frac{5}{12} + \frac{3}{20} × \frac{10}{9} =$

答案： $\frac{3}{20} × \frac{10}{9} = \frac{30}{180} = \frac{1}{6}$，$\frac{5}{12} + \frac{1}{6} = \frac{5}{12} + \frac{2}{12} = \frac{7}{12}$

㉑ $20 × (1 - \frac{3}{4}) =$

答案： $1 - \frac{3}{4} = \frac{1}{4}$，$20 × \frac{1}{4} = 5$

㉒ $(\frac{7}{9} - \frac{1}{7}) × 63 =$

答案： $\frac{7}{9} × 63 = 49$，$\frac{1}{7} × 63 = 9$，$49 - 9 = 40$