code: public BigDecimal scaleByPowerOfTen(int n) {
          return new BigDecimal(intVal, intCompact,
                                checkScale((long)scale - n), precision);
      }
docs: Returns a BigDecimal whose numerical value is equal to
  ({@code this} * 10<sup>n</sup>).  The scale of
  the result is {@code (this.scale() - n)}.
  
  @param n the exponent power of ten to scale by
  @return a BigDecimal whose numerical value is equal to
  ({@code this} * 10<sup>n</sup>)
  @throws ArithmeticException if the scale would be
  outside the range of a 32-bit integer.
  
  @since 1.5