• Basic lands : /
ex: 26.6% means that 26,6% of maindeck basic lands in all decks are Plains.
• Other cards : /
ex: Defenestrate 95.1% means that 95.1% of Defenestrate copies are MD, and therefore that 4.9% of them are sideboarded.
Multipliers / Dividers
• Multipliers compare the MD percentage of a given card with the average percentage of cards with the same rarity.
ex: Defenestrate x 1.8 means that the MD percentage of that card (95.1%) is 1.8 times higher than the average for commons (53.4%).
ex: Arcane Infusion ÷ 7.1 means that the MD percentage of that card (9.4%) is 7.1 times lower than the average for uncommons (66.7%) — i.e., you should probably pass it generously to your neighbor.