Câu 1:Trang 114 sách giáo khoa (SGK) toán tiếng Anh lớp 4Make these fractions have amon...

b) To make the fractions $rac{3}{5}$ and $rac{3}{7}$ have a common denominator, we can multiply the first fraction by 7 to get $rac{21}{35}$ and the second fraction by 5 to get $rac{15}{35}$, as 35 is a common multiple of 5 and 7.

a) To make the fractions $rac{5}{8}$ and $rac{1}{4}$ have a common denominator, we can simply multiply the first fraction by 2 to get $rac{10}{16}$ and leave the second fraction unchanged as $rac{1}{4}$, since 16 is a common multiple of 8 and 4.

c) To make the fractions $rac{9}{8}$ and $rac{8}{9}$ have a common denominator, we find the LCM of 8 and 9, which is 72. So we multiply the fractions as follows: $rac{9}{8} = rac{9 imes 9}{8 imes 9} = rac{81}{72}$ and $rac{8}{9} = rac{8 imes 8}{9 imes 8} = rac{64}{72}$. Therefore, the fractions with a common denominator are $rac{81}{72}$ and $rac{64}{72}.

b) To make the fractions $rac{3}{5}$ and $rac{3}{7}$ have a common denominator, we find the LCM of 5 and 7, which is 35. So we multiply the fractions as follows: $rac{3}{5} = rac{3 imes 7}{5 imes 7} = rac{21}{35}$ and $rac{3}{7} = rac{3 imes 5}{7 imes 5} = rac{15}{35}$. Therefore, the fractions with a common denominator are $rac{21}{35}$ and $rac{15}{35}$.

a) To make the fractions $rac{5}{8}$ and $rac{1}{4}$ have a common denominator, we need to find the Least Common Multiple (LCM) of 8 and 4, which is 8. So we multiply the numerator and denominator of $rac{5}{8}$ by 1 (which is equivalent to $rac{1}{1}$): $rac{5}{8} = rac{5 imes 1}{8 imes 1} = rac{5}{8}$. For $rac{1}{4}$, we multiply the numerator and denominator by 2: $rac{1}{4} = rac{1 imes 2}{4 imes 2} = rac{2}{8}$. Therefore, the fractions with a common denominator are $rac{5}{8}$ and $rac{2}{8}$.