A joke that nerds usually make about the rounding of numbers. If you do 2.3 rounded (2) + 2.4 rounded (2), you get 4.7 which rounds to 5.
And because humans are imperfect, we are never able to make exact precision on anything. This means, that anything we do, we are doing some kind of rounding/estimation at some point. So, this means that 2 + 2 = 5 but only for very large values of 2.