Have you ever had a problem with "два"?

Apart from “one” that has three different variants in Russian (ОДИН / ОДНА / ОДНО), “two” is also not as easy as one-two-three! It has two variant too: ДВА / ДВЕ.

- See more at: http://enjoyrussian.com/russian-numbers/#sthash.tfVsJOX5.dpuf