[tex]a = \frac{60}{50} \\ a = \frac{6 \times 10}{5 \times 10} \\ a = \frac{6}{5} [/tex]
[tex]b = \frac{21}{27} \\ b = \frac{7 \times 3}{9 \times 3} \\ b = \frac{7}{9} [/tex]
[tex]c = \frac{90}{135} \\ c = \frac{ 2\times 45}{ 3\times 45} \\ c = \frac{2}{3} [/tex]
[tex]d = \frac{78}{24} \\ d = \frac{13 \times 6}{4 \times 6} \\ d = \frac{13}{4} [/tex]
