what is the difrence between 二&两 and 俩？？？plz（all of those mean number two)

The easiest explanation that 二 is the numeral two or second. 兩 means pair, couple.  As in English, the same difference between "two/second" and "a pair".

倆 has another meaning - "craft" or "ability".  The other means "pair", "couple".  The difference is that a classifier is not allowed after it!

倆錢兒 not much money 

倆人 a couple as in a couple in love

倆月 couple of months as opposed to 兩个月

咱倆  we two

夫妇倆 husband and wife.

Also 二 is used in formal, poetic or classical forms.

二月 = Feburary not two months in modern usage.  Can also mean two months in classical Chinese depending on context!

二人 = two people, more of classical Chinese style and poetic form.

二心 = two hearts = disloyalty different from the literal two "hearts" as in 兩个心 or 俩心

二胡 = two string fiddle, never 俩胡 or 兩个胡 (two barbarians)

二老 = two venerables ie parents

二八 = two eights or 16 as in 二八年华, youth of 16, poetic usage

二百五 = two hundred and fifty ie simpleton, blockhead

二房 = second room ie concubine

二房東 = land lord who himself is a renter (modern usage) The concubine in power (classical euphemism)

二度梅 = euphemism for a remarried woman

二重    = dual

二年 = biennial