A chest of treasure was hidden in the year 64 BC and found in 284 AD. For how long was the chest hid

[math_celebrity]

A chest of treasure was hidden in the year 64 BC and found in 284 AD. For how long was the chest hidden

BC stands for Before Christ. Year 0 is when Christ was born. AD stands for After Death

On a number line, the point of Christ's birth is 0.
So BC is really negative
AD is positive

So we have:
284 - -64
284 + 64
348 years