Tính \( 21 \frac{1}{5} : 16 - \frac{5}{2} \)
Tính hợp lí nếu có thể
----- Nội dung ảnh -----
13) \( 21 \frac{1}{5} : 16 - \frac{5}{2} ; \)
14) \( \frac{11}{15} \left( - \frac{19}{13} \right) + \frac{11}{15} \left( - \frac{7}{13} + \frac{4}{5} \right) ; \)
15) \( \frac{7}{9} - \frac{11}{21} - \frac{4}{21} \frac{7}{9} ; \)
16) \( \frac{5}{14} - \frac{12}{2} - \frac{5}{14} \cdot \frac{1}{2} ; \)
17) \( 20 \frac{12}{13} - 16 \frac{8}{9} - 20 \frac{12}{13} - 42 \frac{8}{9} ; \)
18) \( 1 \frac{7}{9} : \left( - \frac{10}{3} \right) + 1 \frac{2}{9} \left( - \frac{10}{3} \right) ; \)
----- Nội dung ảnh -----
13) \( 21 \frac{1}{5} : 16 - \frac{5}{2} ; \)
14) \( \frac{11}{15} \left( - \frac{19}{13} \right) + \frac{11}{15} \left( - \frac{7}{13} + \frac{4}{5} \right) ; \)
15) \( \frac{7}{9} - \frac{11}{21} - \frac{4}{21} \frac{7}{9} ; \)
16) \( \frac{5}{14} - \frac{12}{2} - \frac{5}{14} \cdot \frac{1}{2} ; \)
17) \( 20 \frac{12}{13} - 16 \frac{8}{9} - 20 \frac{12}{13} - 42 \frac{8}{9} ; \)
18) \( 1 \frac{7}{9} : \left( - \frac{10}{3} \right) + 1 \frac{2}{9} \left( - \frac{10}{3} \right) ; \)