A number really get Information Technology (5)
I believe the answer is:
digit
'a number' is the definition.
(digit is a kind of number)
'really get information technology' is the wordplay.
'really get' becomes 'dig' (to dig can mean to appreciate or 'get').
'information technology' becomes 'it' (common abbreviation).
'dig'+'it'='DIGIT'
(Other definitions for digit that I've seen before include "Like It?" , "zero, one, two, three, four, five, six, seven, eight, or nine" , "A small number" , "finger, perhaps" , "Finger; numeral" .)