Do battle card effects stack?

Many battle cards provide buffs to Mario/Luigi/Paper Mario, including raising stats or coins/exp gained from battle. Debuffs can also be applied to enemies, lowering their stats.

There are also cards that have the same effect, but different magnitudes/circumstances. I currently have in my deck cards that give +25% experience, +50% experience, and 100% experience if the enemy is defeated on the next turn.

Do these effects stack if...

1. Two different cards are used (Say I use the +25% exp and +50% exp in succession to attempt to get +75% exp)?
2. The same card is used twice in a single battle (Say I use the +50% exp, it was the last card so the deck is reshuffled, and I can use the +50% exp again if it is flipped early)?