The task is to read a passage and convert numbers in their text forms into digit forms. The text numbers can be used to represent Quantity, Dates and Time, Addresses or Positions.

Let me give you an example: Jacob ate three burgers today.
The answer to this example can be: Jacob ate 3 burgers today.
Here is why: The number in text form three is converted into the number in digit form 3.

OK. solve this:
At the time of the assassination the names of about one hundred persons were in this index, all of whom were included in the group of four hundred
Answer:
At the time of the assassination the names of about 100 persons were in this index, all of whom were included in the group of 400