43 x 3 tens equals how many tens

Select all the correct answers. what is 221,000,000,000,000,000,000 expressed in scientific notation?

According to modern science, earth is about 4.5 billion years old and written human history extends back about 10,000 years. suppose the entire history of earth is represented with a 10-meter-long timeline, with the birth of earth on one end and today at the other end.

What function has a range {yly< 5}? question on picture above^