Not a whole deal this week, or even a single hand, just one suit.
It is useful to know some common suit combinations so that you don't have to work them out at the table.
Here you have to play this suit for a) three tricks, b) four tricks.
Assume that there are plenty of entries to either hand and that you have no extra information about the distribution of the suit from the bidding or play so far.
You can always make three tricks with this combination. Four tricks cannot be guaranteed, but there is a slight improvement to the natural looking line of play.
Solution and analysis
Three tricks can be guaranteed by playing the king first and then the five towards dummy, covering West's card. If West shows out then play the ace and lead towards the jack.
For four tricks the best chance is to find East with the queen. However it does not help to play the ace first. If West has a singleton queen then East's 10876 will make a trick. Playing the 2 from dummy will gain, however, if East has a singleton queen. So the correct line is small from dummy intending to finesse the jack.