In order to mark something as 'equal to, or more than (A)', 以上（いじょう） will be used. This is simply a combination of the kanji 以（い） which means 'by means of', and 上（じょう） 'above'. This expression may also be translated as 'greater than (A)', or 'exceeding (A)'.
To use 以上（いじょう）, attach it to the amount that you want to highlight as the 'minimum' amount.

• 70歳（さい）以上（いじょう）の人（ひと）は運転（うんてん）をしない方（ほう）がいい。
  It would be better if people over the age of 70 didn't drive.
• コンサートには500人（にん）以上（いじょう）のファンが集（あつ）まった。
  More than 500 fans gathered at the concert.

以上（いじょう） is also regularly used as a statement that translates roughly as 'the end', or 'that's it', and is a very common way to say that something has finished.

• え～っと、ビッグマックのセットとクォーターパウンダーの単品（たんぴん）とナゲットの30ピースを下（くだ）さい。以上（いじょう）です。
  Uhhh, Can I have a Big Mac meal, a quarter pounder, and 30 nuggets? That's all.

Although saying 'the end' would sound a bit rude in English in this situation, it is completely natural in Japanese, and literally means 'the above (list of things I said) is all'.