What times what equels 900

Compare the subtraction problems 6/8 - 5/8 = 1/8 and 6/9 - 7/9 = 1/9 why is the answer to the first problem positive and the answer to the second problem negative

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.

Enter numbers to write 0.000328 0.000328 in scientific notation. 1 1 0.000328=3.28 × 0 . 000328 = 3 . 28 × =3.28×10 = 3 . 28 × 10