Estimating Population
Domain: Operations and Algebraic Thinking
Standard: 4.OA.3 – Read and write multi-digit whole numbers using base-ten numerals and number names. Assess the
reasonableness of answers using mental computation and estimation strategies including rounding in a multi-step word problem.
Launch:
Ask the students the following “Lead-in” questions:
*What is a population?
*Why is population important? What would a city use this information for?
*How can we come up with the population of our city?
*Is there an easier way to count the people rather than one by one?
Provide students with the current population of Utah. (2,817,222). Inform them that the largest city in Utah is Salt Lake City and it
has the largest population in the state. Tell them that one of the smallest cities in Utah is Axtell, and it has the smallest population in
the state.
Discovery Task:
Your task is to estimate the total population of our city. Record your answers in standard number form along with all information,
calculations, and diagrams used to arrive at your estimate.
As you begin putting together groups of people that you know within the city, think about those people that are the closest to you:
Ask yourselves:
*How many people are in this classroom?
*How many people are there in all the families of the students in this classroom?
*How many families like this are in this school?
*How many schools are in this city? Don’t forget to include elementary schools, jr. high schools, and high school.
*Include groups of people that don’t go to school such as aunts, uncles, grandparents.
*Can you think of a way to diagram the groups of people?
Sharing and Discussing:
Invite the students to share their estimates of the population of our city using specific estimations from smaller groups within the
city.
Tell the students to justify their estimations.
After every group has presented their estimates, share with the class that Salt Lake City, the largest city in our state, has a
population of 186,440 and Axtell, one of the smallest cities in our state, has a population of 253. Ask: “Our city is neither the smallest
nor the largest city in the state… is your estimate reasonable?”
Extension:
Figure the population of Davis County? How does the size of our city compare to the size of other cities in our county by population?
Why would that information be helpful or important to know?