Growth and decay

What you'll learn

1. 1

   Imagine a bacteria colony that doubles every hour. That's growth — it gets bigger over time.

2. 2

   Which of these is an example of growth?

3. 3

   A bacteria population starts at 100 and doubles every hour. How many after 3 hours?

4. 4

   Drag the slider to show the bacteria count after 2 hours, starting at 50 and doubling each hour.

5. 5

   A radioactive sample has 80 g and loses half its mass each year. How much remains after 2 years?

6. 6

   Use the bar model to show a population of 200 that grows by 50% (adds half its size) in one step.

7. 7

   If a tree grows by 10% each year and is 2 m tall now, how tall is it after 1 year?