[tex] 0.63 = \frac{63}{100} [/tex]

[tex]0.21 = \frac{21}{100} [/tex]

[tex]0.2(3) = \frac{23 - 2}{90} = \frac{21}{90} = \frac{7}{30} [/tex]

[tex]0.12(4) = \frac{124 - 12}{900} = \frac{112}{900} = \frac{28}{225} [/tex]