A gymnastics score has two halves: the D-score counts difficulty, while the E-score starts at 10.0 and loses points for every execution error.
Almost everyone assumes harder means more points. The D-score is actually built from three blocks: the difficulty value of your best eight elements plus the dismount (men's programme), the element-group requirements (four groups per apparatus, worth up to 2.0 points together) and connection value, on floor up to 0.2 points for elements linked directly. The classic mistake is the ninth hard element: it adds nothing to the D-score, yet it burns energy and invites E-score deductions. Work your routine out on paper instead of by feel. What tends to get missed: the four element groups differ on every apparatus, so a high bar strategy doesn't carry over to pommel horse. Rhythmic gymnastics adds a third mark, A for artistry, weighing as much as difficulty; trampoline adds laser-measured flight height.