Balancing Chemical Equations using fractions?

Ok, may be a a silly question but i dont understand how they came up with these fractions to balance this chemical equation. Can someone explain it to me?

NH2CH2COOH (s) + 9/4 O2 -----> 2 CO2 (s) + 5/2 H2O (l) + 1/2 N2 (g)

Thank you!
Update: Ok how are they coming up with mols, i need to be able to do this on a test.. like put these fractions in i guess and i dont know how to come up with it.
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