A petri dish originally contained 140 bacteria. A scientist let the bacteria grow and now there are 870 of them. How many more bacteria are there now?

1. Break Down the Problem

To find out how many more bacteria are present now compared to the original amount, we need to calculate the difference between the current number of bacteria and the original number of bacteria.

2. Relevant Concepts

The formula to find the difference between two quantities is: $\text{Difference} = \text{Current Amount} - \text{Original Amount}$

3. Analysis and Detail

1. Original Amount of Bacteria: 140
2. Current Amount of Bacteria: 870
3. Calculate the Difference: $\text{Difference} = 870 - 140$

4. Verify and Summarize

Perform the calculation: $870 - 140 = 730$

Final Answer

There are 730 more bacteria now.