standard_description: Count within 1000; skip-count by 5s, 10s, and 100s.
problem_activity: Task
Historians estimate that there were about 7 million people on the earth in 4,000 BCE. Now there are about 7 billion! We write 7 million as 7,000,000. We write 7 billion as 7,000,000,000. How many times more people are there on the earth now than there were in 4,000 BCE?


aligns: no