Patterns in Whole Numbers

What comes between $22$ and $24$$?$

Find the difference :$13006-9999$

Find the difference between the smallest number of $7$ digits and the largest number of $4$ digits.

Find the difference: $13006-9999$

Find the odd one.

A code series is given in which letters and numbers (or digits) are placed together in a specific pattern. Tick the code which comes next. $\mathrm{AB}18, \mathrm{CD}27, \mathrm{EF}36, \mathrm{GH}45,$ ?

A code series is given in which letters and numbers (or digits) are placed together in a specific pattern. Tick the code which comes next. $\mathrm{XX}12, \mathrm{WW}23, \mathrm{VV}34, \mathrm{UU}45,$ ?