Answer:
The plates have moved across Earth’s surface for hundreds of millions of years. As the plates move, the continents on them move, too. This movement is called continental drift.
Scientists think that it takes about 500 million years for all the continents to join together into one big continent—or supercontinent—and then break apart again. A number of supercontinents have formed and broken apart on Earth over time. The most recent supercontinent, called Pangea (or Pangaea), had formed by about 270 million years ago. Pangea lay across a plate boundary. Slowly, Pangea broke apart at this boundary. Rising magma filled in the space, which eventually became the floor of the Atlantic Ocean.
One piece of Pangea included parts of what are now North America, Europe, and Asia. This piece, called Laurasia, drifted north. The other piece of Pangea included parts of what are now Antarctica, Africa, South America, and Australia. This part, called Gondwanaland, drifted south. Eventually Laurasia and Gondwanaland broke apart, too. The continents then slowly moved to the places they are now.
The continents continue to move today. Scientists believe that in about 250 million years they will join together again.
Explanation:
1/2 * 20 = 10
You can also think of it as the 20 being divided by two.
