Learning the meaning of each card is only part of the story. The real power of reading Tarot comes from being able to interpret the way in which the cards combine with each other. Taking into account reversals, there are over 24,000 (78 x 77 x 4) permutations of any 2 card combinations, so it is impossible to learn each one. However, as a reader you don't need to. You just need to learn how to combine the card meanings together and apply that combined meaning to the card position. With the Pentagram spread (and other spreads such as the Celtic Cross), you would also apply the meaning in the context of the centre cards.

Let us examine a few examples:

Position	Past
First Card	Page of Wands Reversed
Second Card	Death
Details	As we are in the past position the Page ("childhood anger") could refer to the querent's own past or child mentality, with the Death card ("letting go") we are having a challenge of letting go
Interpretation	(i) Being unable to let go of childhood anger, or (ii) being unable to let go of an idea or project
Position	Hopes/Fears
First Card	5 of Cups
Second Card	Wheel of Fortune
Details	Here we will find out what is of major concern to the querent with a 5 Cups ("focus on whats missing"). I would definitely judge this as a fear. The querent is only able to see a negative outcome of some action with the Wheel of Fortune ("cycle of events"), so there would be a fear of repeating this cycle
Interpretation	Being fearful of repeating past negative experience
Position	Challenge
First Card	Temperance
Second Card	2 of Wands Reversed
Details	The challenge is what the querent needs to do (or to avoid) in order to achieve the outcome. Here we have Temperance ("focus on health & healing") combined with a reversed 2 Wands ("avoiding a decision"), this can be combined to apply decision making with the issue of health
Interpretation	You need to face up to a decision relating to your health or wellbeing

As you can see I have taken the individual card meanings and combined them into a single blended meaning and then applied this to the position in the spread. The chances are you will not encounter all the combinations through your entire reading lifetime, and even when you do you always need to apply it in the wider context of the reading.