public function subtractionLarge() { $a = new BigInt('3648687239856798163884314322850602640980469152653015254546051651870'); $b = new BigInt('1067825251034421530837885294271156039110655362253362224471523'); $r = new BigInt('3648686172031547129462783484965308369824430041997653001183827180347'); $this->assertEquals($r, $a->subtract($b)); }