For a two digit number, the number on the one digit is 1 times larger than the number on the ten digit number; if the number on the ten digit number is exchanged with the number on the one digit number, the new number is 45 times larger than the original number, then the original two digit number is 1______ ．

For a two digit number, the number on the one digit is 1 times larger than the number on the ten digit number; if the number on the ten digit number is exchanged with the number on the one digit number, the new number is 45 times larger than the original number, then the original two digit number is 1______ ．

Let the single digit of this two digit number be x and the ten digit number be y. then x = 2Y + 1 (10Y + x) + 45 = 10x + y. the solution is x = 9y = 4. Then the original two digit number is 49, so the answer is 49