1.1 Introduction to whole numbers  (Page 5/13)

Round $843$ to the nearest ten.

Solution

Locate the tens place.
Underline the digit to the right of the tens place.
Since 3 is less than 5, do not change the digit in the tens place.
Replace all digits to the right of the tens place with zeros.
	Rounding 843 to the nearest ten gives 840.

Got questions? Get instant answers now!

Got questions? Get instant answers now!

Round each number to the nearest hundred:

1. ⓐ $\mathrm{23,658}$
2. ⓑ $\mathrm{3,978}$

Solution

ⓐ
Locate the hundreds place.
The digit of the right of the hundreds place is 5. Underline the digit to the right of the hundreds place.
Since 5 is greater than or equal to 5, round up by adding 1 to the digit in the hundreds place. Then replace all digits to the right of the hundreds place with zeros.	So 23,658 rounded to the nearest hundred is 23,700.

ⓑ
Locate the hundreds place.
Underline the digit to the right of the hundreds place.
The digit to the right of the hundreds place is 7. Since 7 is greater than or equal to 5, round up by added 1 to the 9. Then place all digits to the right of the hundreds place with zeros.	So 3,978 rounded to the nearest hundred is 4,000.

Got questions? Get instant answers now!

Got questions? Get instant answers now!

Round each number to the nearest thousand:

1. ⓐ $\mathrm{147,032}$
2. ⓑ $\mathrm{29,504}$

Solution

ⓐ
Locate the thousands place. Underline the digit to the right of the thousands place.
The digit to the right of the thousands place is 0. Since 0 is less than 5, we do not change the digit in the thousands place.
We then replace all digits to the right of the thousands pace with zeros.	So 147,032 rounded to the nearest thousand is 147,000.

ⓑ
Locate the thousands place.
Underline the digit to the right of the thousands place.
The digit to the right of the thousands place is 5. Since 5 is greater than or equal to 5, round up by adding 1 to the 9. Then replace all digits to the right of the thousands place with zeros.	So 29,504 rounded to the nearest thousand is 30,000.

Notice that in part ⓑ , when we add $1$ thousand to the $9$ thousands, the total is $10$ thousands. We regroup this as $1$ ten thousand and $0$ thousands. We add the $1$ ten thousand to the $3$ ten thousands and put a $0$ in the thousands place.

Got questions? Get instant answers now!

Got questions? Get instant answers now!

Key concepts

• Name a whole number in words.
  1. Starting at the digit on the left, name the number in each period, followed by the period name. Do not include the period name for the ones.
  2. Use commas in the number to separate the periods.
• Use place value to write a whole number.
  1. Identify the words that indicate periods. (Remember the ones period is never named.)
  2. Draw three blanks to indicate the number of places needed in each period.
  3. Name the number in each period and place the digits in the correct place value position.
• Round a whole number to a specific place value.
  1. Locate the given place value. All digits to the left of that place value do not change.
  2. Underline the digit to the right of the given place value.
  3. Determine if this digit is greater than or equal to 5. If yes—add 1 to the digit in the given place value. If no—do not change the digit in the given place value.
  4. Replace all digits to the right of the given place value with zeros.