The sum of two-digit number and the number obtained by reversing the digits is 66. If the digits of the number differ by 2, find the number. How amny such numbers are there?

Form the pair of linear equations in the following problems and find their solutions (if they exist) by any algebraic method :-The sum of a two-digit number and the number formed by interchanging the digits is 110. If 10 is subtracted from the first number, the new number is 4 more than 5 times the sum of the digits in the first number. Find the number

How many 3-digit numbers can be formed by using the digits 1 to 9 if no digit is repeated?

From the pair of linear equations in the following problems and find their solutions (if they exist) by elimination method : The sum of a two digit number and another formed by reversing its digit is 99. Five added to the number yields 4 less than 6 times the sum of its digits. Determine the number.

The total number of 4-digit numbers is