"What is 2 + 2 ?"
The engineer whips out his slide rule (so it's old) and shuffles it back and forth, and finally announces "3.99".
The physicist consults his technical references, sets up the problem
on his computer, and announces "it lies between 3.98 and
4.02".
The mathematician cogitates for a while, oblivious to the rest of the
world, then announces: "I don't know what the answer is, but I can
prove an answer exists!".
Philosopher: "But what do you mean by 2 + 2 ?"
Logician: "Please define 2 + 2 more precisely."
Accountant: Closes all the doors and windows, looks around carefully
then asks "What do you want the answer to be?"
A mathematician will be able to calculate where
the shell will land
A physicist will be able to explain how the
shell gets there
An engineer will stand there and try to catch
it
Mathematician: Pi is the number expressing
the relationship between the circumference of a circle and its diameter.
Physicist: Pi is 3.1415927plus or minus 0.000000005
Engineer: Pi is about 3.