a)
[tex] \frac{13 - 1}{90} = \frac{12}{90} [/tex]
b)
[tex] - \frac{223 - 22}{90} = - \frac{201}{90} [/tex]
c)
[tex] \frac{324 - 3}{990} = \frac{321}{990} [/tex]
d)
[tex] - \frac{123 - 12}{900} = - \frac{111}{900} [/tex]
e)
[tex] \frac{8274 - 82}{990} = \frac{8192}{990} [/tex]
f)
[tex] - \frac{83 - 8}{900} = - \frac{75}{900} [/tex]
