7B
8B
1.
\(\dfrac{27}{36}=\dfrac{27:9}{36:9}=\dfrac{3}{4}\) \(\dfrac{72}{96}=\dfrac{72:24}{96:24}=\dfrac{3}{4}\)
\(\dfrac{64}{48}=\dfrac{64:16}{48:16}=\dfrac{4}{3}\) \(\dfrac{88}{99}=\dfrac{88:11}{99:11}=\dfrac{8}{9}\)
2.
a)\(\dfrac{11}{12}=\dfrac{11\times4}{12\times4}=\dfrac{44}{48}\) ; giữ nguyên \(\dfrac{7}{48}\)
b)\(\dfrac{1}{3}=\dfrac{1\times4}{3\times4}=\dfrac{4}{12}\) ;\(\dfrac{5}{4}=\dfrac{5\times3}{4\times3}=\dfrac{15}{12}\); giữ nguyên \(\dfrac{10}{12}\)
Câu 7:B
Câu 8:B
II
Câu 1:
a)\(\dfrac{27}{36}=\dfrac{27:9}{36:9}=\dfrac{3}{4}\)
b)\(\dfrac{64}{48}=\dfrac{64:16}{48:16}=\dfrac{4}{3}\)
c)\(\dfrac{72}{96}=\dfrac{72:24}{96:24}=\dfrac{3}{4}\)
d)\(\dfrac{88}{99}=\dfrac{88:11}{99:11}=\dfrac{8}{9}\)
Bài 2:
a)\(\dfrac{11}{12}=\dfrac{11\times4}{12\times4}=\dfrac{44}{48};\dfrac{7}{48}\)
b)\(\dfrac{1}{3}=\dfrac{1\times4}{3\times4}=\dfrac{4}{12};\dfrac{5}{4}=\dfrac{5\times3}{4\times3}=\dfrac{15}{12};\dfrac{10}{12}\)
