Bridge problems with all cards exposed are called "double dummy". Here is a deal from a teaching table the other day where you see all 52 cards. South arrived in a normal looking 4♥ after she opened a strong 2♣. Maybe she miscounted, but it's actually an excellent evaluation as the Kaplan & Rubens Hand Evaluator suggests that the hand is worth 22.15.
However, 4♥ has four losers, two in each minor (unless West cashes ♦A or beats thin air if a diamond is played toward dummy), whereas 3NT is a make even on a club lead because East has no entry. In fairness, it is very difficult to get to 3NT when you have a 5-4 fit in a major.
The student, understandably, went one down in 4♥ after West led the jack of spades. Could she have made it with all cards in view?
Please remember that this is the Beginner and Intermediate forum, so if your skill level is higher, you are kindly requested to refrain from answering (or at least use hidden text) until the B&I's have had a chance to get a closer look.
Roland
S: 4H
Lead: Spade Jack