if u used the wrong mana can you use different mana? magic

[Dude]

if you used the wrong mana can u use different mana?

[Arix]

Depends what you mean by "wrong". Was it illegal, or just a bad choice?

[Dude]

I have 2 green lands and 1 red land and I tap the 2 green lands to play plummet but then i want to play giant growth but my green lands are used but because plummet didnt require 2 green lands i could have used 1 green land and 1 red land so can i say i used the green land and the red land for mana and that way i still have green land left for giant growth because i could have used 1 green and 1 red for plummet

[Arix]

If this is just a casual game, then I'd invoke the "don't be a dick" rule and let you take it back and re-tap your mana.

A good habit to get into is, when you want to play multiple spells at once, tap all your lands at once.