999999999999700000
Pascal AC simple solution give 999999999.9999, but Maple returns 999999999.9998499999999999887... that must be rounded (and even truncated) to 999999999.9998

Study mathematics, 999999999.99984(9)9 this one make next digit to become from 4 to 5, and 5 is rounding up, thats why you get 9