So, in my last post I was asking how to build a dynamic search filter using LINQ and EF4 (See Here) and finally came up with the solution of building the expression as a str
I haven't got a clue if this will work over Linq to EF or not but presuming that they mapped the Math operations, this might solve your need:
record.ConsecutiveNumber / Math.Pow(10, Math.Truncate(Math.Log10(record.ConsecutiveNumber) - 3)) == 1234
This is basically dividing the number by a power of 10 just big enough to leave the first 4 digits.
I know this is very hacky and inefficient even if it works, but there you go. :)