Why do 'I'm up for it' and 'I'm down for it' mean the same thing

Meaning of I'M DOWN FOR IT and I'M UP FOR IT - A Short English Lesson with Subtitles

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차이점은 무엇 입니까? I'm down for it 그리고 I'm up for it ?

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ARIN :: - іᑲ :: mᥱ (?) / 𝗍ᥲg - 𝖿ᥲᥒᥴᥲm :: ᥲrіᥒ [᥆һ mᥡ gіrᥣ] - 𝗍ᥲggі

What's the difference between being 'up' or 'down' for something? - Quora

Why do 'I'm up for it' and 'I'm down for it' mean the same thing? - Quora

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