Best Answer - Chosen by Voting
Hi! @KakiArisu. I wrote about my opinion.
1. ”以上” have some meanings, such as "more than", "over" or "above".
ex: 私は３０分以上待ちました。 I waited for more than 30 minutes.
この車は時速１００ｋｍ以上で走れる。 This car can run at over 100 kilometers.
彼の成績は平均以上だった。 His grades were above average.
2. ”以下” have some meanings, such as "less than", "below" or "under".
ex: この靴は８千円以下で売ります。 I will sell this shoes for less than 80,00yen.
彼女は４０歳以下だろう。 She may be under forty.
今日の気温は１０度以下に下がった。 today's temperature dropped below 10 degrees.
