The Igorot subtracts by addition.
"The Bontoc Igorot"
Albert Ernest Jenks
The Admiral, fallen into theological stupor, puts down certain figures upon paper; discovers that St. Augustine said that the world would only last for 7000 years; finds that some other genius had calculated that before the birth of Christ it had existed for 5343 years and 318 days; adds 1501 years from the birth of Christ to his own time; adds up, and finds that the total is 6844 years; subtracts, and discovers that this earthly globe can only last 155 years longer.
"Christopher Columbus, Volume 7 And The New World Of His Discovery, A Narrative"
Filson Young
The notion that Sanskrit itself is comparatively recent, of course subtracts from that of Brahminism.
"The Ethnology of the British Colonies and Dependencies"
Robert Gordon Latham