1. Population Math

2. Growth Rate for a Nation or Region = (CBR + I) – (CDR + E)
CBR = Crude Birth Rate
I = Immigration
CDR = Crude Death Rate
E = Emmigration

3. Example 1
Jan , the population of a small suburb in Los Angeles was 20,000. Birth rate was 25 per 1000 population. Death rate was 7 per 1000 population. Immigration was 600 per year. Emigration was 200 per year. By how much did the population increase by Jan 1, 1951?

4. Example 2
The tiny county of Fremont has a population of 100,000 people. In 2009, there were 20 births per 1000 population, 5 deaths per 1000 population, 200 emigrants, and 100 immigrants. What is the population growth rate for 2009?

5. Population % Change Calculation
(P present or future – P past or present) x 100=
Ppast or present

6. Example 1
In 1980, the population of a city was 250,000. In 1990, the population of the city grew to 280,000. Calculate the % change.

7. Equation for determining how long it takes for a population to double:
Rule-of-70:
n = 70/r
n = number of years
r = % rate of growth

8. For example, a city with an annual population growth rate of 5% will double its population in approximately…
70/5 = 14 years
#2 If the growth rate were 7%, it would double its population in approximately ?