俩→The back can be a direct object，For example，俩人，俩包子... 两→Behind the general connection classifier，For example，两个包子，两台电视... The most important is the different pronunciation，俩＝lia(三声）两＝liang(三声） Hope it helps you out.

俩=两个 As you can see, 俩 is composed of two parts, 两 （two）and 个 （measure word）. In which case, you can say 两个苹果， but you don't say 俩个苹果。 两个月=俩月=two months 两张桌子=俩桌子= two tables 两条领带=俩领带= two ties ... For those that don't need measure words. such as years, days, nights, minutes, seconds ...（Those nouns are somehow measurable by themselves）. in which case you can't use 俩. So you can only say 两天、两年、两周、两分钟, we never say 俩天、俩年、俩周、俩分钟 However 星期、月、小时 need measure words, so you can say “两个星期”、“两个月”、“两个小时”，you can also say “俩星期”、“俩月”、“俩小时”. Haha... it seems complicated, I hope this doesn't come off too confusing.

亲爱！谢谢你！：）

筱伟 is correct, and 三 and 仨 have the same relation.