List of top Quantitative Aptitude Questions on Number Systems asked in BHU PET

If a number \( x \) be subtracted from each of the numbers 21, 38, 55, 106, then they become proportional. The value of \( x \) is:
The difference of the place value and the face value of the digit 2 in 3124698 is:
If one is added to the second digit of each number and one is subtracted from the third digit of each number and then if the first and third digits of each number are interchanged, then which number will be lowest?