Practice: activating prior knowledge
write three real-world examples of quantities that you would use scientific notation to express.
(hint: what measurements are really large or really tiny? )

Scientific notation is used to write really large numbers, or really small numbers using less digits. For example: 

1. Earth's distance from the sun 150,000,000 kilometers. We can rewrite this in scientific notation as 1.5 x 

2. The length of a skin cell is 0.00003 meters. We can rewrite this in scientific notation as 3.0 x 

3. The world population is about 7,000,000,000. We can rewrite this in scientific notation as 7 x