excel vba- extract text between 2 characters

You can use instr to locate a character within the string (returning the position of '(' for example). You can then use mid to extract a substing, using the positions of '(' and ')'.

Something like (from memory):

dim str as string
dim openPos as integer
dim closePos as integer
dim midBit as string

str = "NUMBER(8,3)"
openPos = instr (str, "(")
closePos = instr (str, ")")
midBit = mid (str, openPos+1, closePos - openPos - 1)

You may want to add error checking in case those characters don't occur in the string.