## Thinking Mathematically (6th Edition)

a. $37,691,900$ b. $37,692,000$ c. $37,690,000$ d. $37,700,000$ e. $38,000,000$ f. $40,000,000$
We can select the state of California for this exercise. Its population is $37,691,912$. We need to round the population of the state to the nearest: a. hundred b. thousand c. ten thousand d. hundred thousand e. million f. ten million To do this exercise, we need to remember how we round numbers: 1. Look at the digit to the right of the digit where rounding is to occur. 2a. If the digit to the right is $5$ or greater, add $1$ to the digit to be rounded. 2b. If the digit to the right is less than $5$, do not change the digit to be rounded. 3. Replace all digits to the right with zeros. a.Rounding to the nearest hundred: The hundreds digit is $9$, and the digit behind it is $1$, which is less than $5$; therefore, we have to keep the hundreds digit the same, giving us the following number: $37,691,900$ b.Rounding to the nearest thousand: The thousands digit is $1$, and the digit behind it is $9$, which is greater than $5$; therefore, we have to increase the thousands digit by $1$, giving us the following number: $37,692,000$ c.Rounding to the nearest ten thousand: The ten thousands digit is $9$, and the digit behind it is $1$, which is less than $5$; therefore, we have to keep the ten thousands digit the same, giving us the following number: $37,690,000$ d.Rounding to the hundred thousand: The hundred thousands digit is $6$, and the digit behind it is $9$, which is greater than $5$; therefore, we have to increase the hundred thousands digit by $1$, giving us the following number: $37,700,000$ e.Rounding to the nearest million: The millions digit is $7$, and the digit behind it is $6$, which is greater than $5$; therefore, we have to increase the millions digit by $1$, giving us the following number: $38,000,000$ f.Rounding to the nearest ten million: The ten millions digit is $3$, and the digit behind it is $7$, which is greater than $5$, and therefore, we have to increase the ten millions digit by $1$, giving us the following number: $40,000,000$