Tính :
a) 351 : 54 8,46 : 3,6 204,48 : 48
b) \(\displaystyle\frac{{14}}{{15}}:\frac{7}{{20}}\) \(\displaystyle{9 \over 8}:{{27} \over {16}}\)
a)
b)
\(\displaystyle\frac{{14}}{{15}}:\frac{7}{{20}}=\frac{{14}}{{15}}\times\frac {20}{{7}}=\dfrac{14\times 20}{15 \times 7} \displaystyle=\dfrac{7\times 2 \times 5 \times 4}{5\times 3 \times 7}= \dfrac{8}{3} \\\displaystyle{9 \over 8}:{{27} \over {16}}=\frac{{9}}{{8}}\times\frac {16}{{27}}=\dfrac{9\times 16}{8 \times 27} \displaystyle=\dfrac{9\times 8\times 2}{8\times 9 \times 3}= \dfrac{2}{3}\)
-- Mod Toán lớp 5