Bài 1 trang 15 SGK Toán 5
Đề bài
Tính:
a) \( \frac{7}{9}+\frac{9}{10}\) ; b) \( \frac{5}{6}+\frac{7}{8}\) ; c) \( \frac{3}{5}+\frac{1}{2}+\frac{3}{10}\) .
Hướng dẫn giải
a) \( \frac{7}{9}+\frac{9}{10}\) \( =\frac{70}{90}+\frac{81}{90}=\frac{151}{90}\) ;
b) \( \frac{5}{6}+\frac{7}{8}\) \( =\frac{20}{24}+\frac{21}{24}=\frac{41}{24}\) ;
c) \( \frac{3}{5}+\frac{1}{2}+\frac{3}{10}= \frac{6}{10}+\frac{5}{10}+\frac{3}{10}\)
\(=\frac{6+5+3}{10}=\frac{14}{10}=\frac{7}{5}\) .