a) \(\dfrac{12}{15}+5=\dfrac{4}{5}+5=\dfrac{4}{5}+\dfrac{25}{5}=\dfrac{29}{5}\)
b) \(\dfrac{7}{10}-\dfrac{6}{10}=\dfrac{1}{10}\)
c) \(\dfrac{3}{5}x\dfrac{5}{6}=\dfrac{15}{30}=\dfrac{1}{2}\)
d) lỗi
a) \(\dfrac{12}{15}+5=\dfrac{4}{5}+5=\dfrac{4}{5}+\dfrac{5}{1}=\dfrac{4}{5}+\dfrac{25}{5}=\dfrac{29}{5}\)
b) \(\dfrac{7}{10}-\dfrac{3}{5}=\dfrac{7}{10}-\dfrac{6}{10}=\dfrac{1}{10}\)
c) \(\dfrac{3}{5}\times\dfrac{5}{6}=\dfrac{3\times5}{5\times6}=\dfrac{15}{30}=\dfrac{1}{2}\)
d) Thiếu số