Slight different case of multiple condition with regard to if

Here:

Formula:

Please Login or Register  to view this content.

You wrote correct.

CHOOSE function return n-th value defined by index number.

Formula:

Please Login or Register  to view this content.

If index_num is 1, CHOOSE returns value1; if it is 2, CHOOSE returns value2; and so on.

In your case you need to return:,"",38,43,"" wehre index_num is defined by value in K1 (1,2,3 or 4)
If K1 is bigger than 4 you will get error (because 5th value in CHOOSE function is not defined).
But since they are all same after 4th value you can use always that value (4) so you need

Formula:

Please Login or Register  to view this content.

That will return 1,2,3 or 4

Please Login or Register  to view this content.

If this not the case, if values after 4 are different, then you need to define all of them in CHOOSE function.
That would make CHOOSE function too huge and I would rather go with VLOOKUP function in that case (but that's another sotry).

At the end, let's sumarize once again:
Index_num 3 will return 3rd value in your choose function that is 43

Formula:

Please Login or Register  to view this content.

Another way..
=IF(K1>=4,J4+6,INDEX({"",6,43},K1))

answer to your second question would be
=INDEX({"",38,43,""},MIN(K1,4))