[tex]20.\\15cd=(3)(5)cd\\25cd^3=(5)(5)cddd\\\\LCM(15cd,\ 25cd^3)=(3)(5)(5)cddd=75cd^3\\\\21.\\5g^2h^3=5gghhh\\19g^3h=19gggh\\\\LCM(5g^2h^3,\ 19g^3h)=(5)(19)ggghhh=95g^3h^3\\\\23.\\\\Multiples\ of\ 12:\ 0,\ 12,\ \boxed{24},\ 36,\ ...\\Multiples\ of\ 3:\ 0,\ 3,\ 6,\ 9,\ 12,\ 15,\ 18,\ 21,\ \boxed{24},\ 27,\ ...\\Multiples\ of\ 24:\ 0,\ \boxed{24},\ 48,\ 72,\ ...\\\\24=12\cdot2,\ 24=3\cdot8[/tex]
[tex]\dfrac{5}{12}=\dfrac{5\cdot2}{12\cdot2}=\dfrac{10}{24}\\\\\dfrac{1}{3}=\dfrac{1\cdot8}{3\cdot8}=\dfrac{8}{24}\\\\\dfrac{8}{24} <\dfrac{10}{24} < \dfrac{11}{24}\\\\Answer:\ \dfrac{1}{3},\ \dfrac{5}{12},\ \dfrac{11}{24}.\\\\24.\\Multiples\ of\ 20:\ 0,\ \boxed{20},\ 40,\ 60,\ ...\\Multiples\ of\ 5:\ 0,\ 5,\ 10,\ 15,\ \boxed{20},\ 25,\ ...\\Multiples\ of\ 10:\ 0,\ 10,\ \boxed{20},\ 30,\ 40,\ ...\\\\20=5\cdot4,\ 20=10\cdot2[/tex]
[tex]\dfrac{3}{5}=\dfrac{3\cdot4}{5\cdot4}=\dfrac{12}{20}\\\\\dfrac{7}{10}=\dfrac{7\cdot2}{10\cdot2}=\dfrac{14}{20}\\\\\dfrac{12}{20} < \dfrac{13}{20} < \dfrac{14}{20}\\\\Answer:\ \dfrac{3}{5},\ \dfrac{13}{20},\ \dfrac{7}{10}[/tex]
