* Calculates square of {@code this.value} according to {@link ral.Real#sqr()}.
* @return new instance of {@code Decimal} which value is square of {@code this.value}.
*/
public Decimal sqr() {
Real result = new Real(this.value);
result.sqr();
return new Decimal(result);
}
/**
* Calculates square root of {@code this.value} according to {@link ral.Real#sqrt()}.