standard_description: Use variables to represent numbers and write expressions when solving a real-world or mathematical problem; understand that a variable can represent an unknown number, or, depending on the purpose at hand, any number in a specified set.
problem_activity: Task
An ant has a mass of approximately $4 \times 10^{−3}$ grams and an elephant has a mass of approximately 8 metric tons.
How many ants does it take to have the same mass as an elephant?
An ant is $10^{−1}$ cm long. If you put all these ants from your answer to part (a) in a line (front to back), how long would the line be? Find two cities in the United States that are a similar distance apart to illustrate this length.
Note: 1 kg = 1000 grams, 1 metric ton = 1000 kg, 1m = 100 cm, 1km = 1000 m


aligns: no