How can teachers encourage their geography students to make sense of big numbers? The key math skills geography students need to apply are ones they learned long ago in fifth grade: estimation and place value. However, in order to recognize the size of a city, or strength of a country's per capita income, or value of a birth rate, they need practice. Using the Population Reference Bureau's 2008 World Population Data Sheet, the author suggests that teachers encourage students to create comparison statements, using math vocabulary. They should model some examples to help students get started. Then they should encourage students to analyze statements. Later, teachers should encourage students to find their own comparison data within a specific region. Quickly, though, students enjoy finding their own interesting sets of data, and learn to express their comparisons with mathematical precision. (Contains 5 tables.)