Another fair question. . . and, again, it depends. Your number will vary by subject, and depend greatly on your level of comfort within each subject. Too few cards, and you risk missing core concepts. Too many, and you risk overwhelming yourself and also defeating the very purpose of index cards: filtration and brevity. Quality should always trump quantity.
Having said that, here are some ballpark ranges you might want to follow. These ranges, of course, vary by student. Some will be comfortable with fewer cards than the ranges suggest, but not many students will have more cards than the ranges.
40 - 55 index cards per subject. With one month before the exam, you should be finished with making index cards. The final month is reserved for learning the cards. Learning 40-55 cards takes a LOT LESS time than trying to memorize 40-55 pages of outline. If you follow the strategy that I teach, these cards will capture the core takeaways within each subject as well as tips and commonly tested tricks.
- First Tier (most commonly tested subjects): 30 - 50 index cards per subject, closer to 50, with two exceptions below 30.
- Second Tier (medium-tested subjects): 15 - 30 index cards per subject, with one or two exceptions potentially below this range.
- Third Tier (least tested subjects): 2 - 15 index cards per subject.
Anyway. . .
Keep studying, and keep your heads up! Refuse to allow stress or anxiety to curb your confidence. You CAN do this! And one more thing - you have permission to responsibly enjoy the Fourth of July next week. Plan for it, in fact. You need nights off to decompress.