1. Tính

Gửi bởi: Phạm Thọ Thái Dương Vào 1 tháng 7 2019 lúc 11:38:32

a) \({3 \over 5} \times {4 \over 7}=\)	\({{12} \over {35}}:{3 \over 5}=\)
\({{12} \over {35}}:{4 \over 7}=\)	\({4 \over 7} \times {3 \over 5}=\)

b) \({{13} \over {11}} \times 2=\)	\({{26} \over {11}}:{{13} \over {11}}=\)
\({{26} \over {11}}:2=\)	\(2 \times {{13} \over {11}}=\)

a) \({3 \over 5} \times {4 \over 7} = {{12} \over {35}};\)

\({{12} \over {35}}:{3 \over 5} = {{12} \over {35}} \times {5 \over 3} = {4 \over 7};\)

\({{12} \over {35}}:{4 \over 7} = {{12} \over {35}} \times {7 \over 4} = {3 \over 5};\)

\({4 \over 7} \times {3 \over 5} = {{12} \over {35}}.\)

b) \({{13} \over {11}} \times 2 = {{26} \over {11}};\)

\({{26} \over {11}}:{{13} \over {11}} = {{26} \over {11}} \times {{11} \over {13}} = 2;\)

\({{26} \over {11}}:2 = {{26} \over {11}} \times {1 \over 2} = {{13} \over {11}};\)

\(2 \times {{13} \over {11}} = {{26} \over {11}}\)