Write first four terms of the $\mathrm{AP}$, when the first term $a$ and the common difference $d$ are given as follows:

$a=4$ and $d=10$

In an Arithmetic progression (A.P.), the fourth and sixth terms are $8$ and $14$ respectively. Find the first term.

The $4^{\text{th}}$ term of an arithmetic progression is $22$ and ${15}^{\text{th}}$ term is $66$. Find the first term and the common difference. Hence, find the sum of the series to $8$ terms.

In an Arithmetic Progression (A.P.) the fourth and sixth terms are $8$ and $14$ respectively. Find the common difference.

If the sum of first four terms of an $\mathrm{AP}$ is $40$ and that of first $14$ terms is $280$. Find the sum of its first $\mathrm{n}$ terms.