var number = new BigInt(1234);

BigInt number = 1234;

BigInt number = "-123456789";

var result = new BigInteger("123456789") + 123456L;
result += "999999";

var result = new BigInteger("123456789") - 123456L;
result -= "999999";

var result = new BigInteger("123456789") * 123456L;
result *= "999999";

var result = new BigInteger("123456789") / 123456L;
result /= "2";

var result = new BigInteger("123456789") % 123456L;
result %= "2";

var result = new BigInteger("123456789").CompareTo("12345676");