Math 952
1.1 "Whole Numbers and Rounding"
Objectives:
*
Learn to read and write whole numbers.
*
Learn how to round whole numbers to a given place.
Reading and Writing Whole Numbers
De…nition:
"Whole Numbers"
The whole numbers are the natural (or counting) numbers and the number 0.
Note that 0 is a whole number but not a natural number.
Note that the three dots (called an ellipsis) indicate that the pattern continues without end.
Writing Whole Numbers in Standard Notation:
To write a whole number in standard notation (or standard form) we use a place
value system that depends on three things:
1: the ten digits: 0; 1; 2; 3; 4; 5; 6; 7; 8; 9;
2: the placement of each digit; and
3: the value of each place.
For example:
Here we notice that every three places constitutes a
with
and the digits in each period are separated
: A number with four or fewer digits need not have any commas.
Page: 1
Notes by Bibiana Lopez
Prealgebra by Franklin Wright
1.1
To read (or write) a number in this system, start from the left and use the name of the number (three digits or less) in each
period.
For example, 7; 839; 076; 532 is read as:
Note:
1: A hyphen ( ) is used when writing two-digit numbers larger than twenty.
2: The word and does not appear as part of reading (or writing) any whole number. The word and indicates the decimal
point.
Example 1: (Writing numbers in words)
The following numbers are written in standard notation. Write them in words.
a) 32; 450; 090
b) 5784
c) 810; 895
d) 25; 000; 000
Example 2: (Writing numbers in standard form)
The following numbers are written in words. Rewrite them in standard notation.
a) six thousand, forty-one
b) nine billion, four hundred eighty-three thousand
c) seven hundred thirty-six
d) one hundred thirteen million, seventy-…ve thousand, four hundred sixty-seven
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Notes by Bibiana Lopez
Prealgebra by Franklin Wright
1.1
Rounding Whole Numbers
Rounding Rule for Whole Numbers:
1: Look at the single digit just to the right of the digit that is in the place of desired accuracy.
2: If this digit is 5 or greater, make the digit in the desired place of accuracy one larger and replace all digits
to the right with zeros. All digits to the left remain unchanged unless a 9 is made one larger; then the next digit
to the left is increased by 1:
3: If this digit is less than 5, leave the digit that is in the place of desired accuracy as it is, and replace all digits
to the right with zeros. All digits to the left remain unchanged.
Example 3: (Rounding numbers)
Round each number to the nearest ten.
a) 762
b) 78
c) 625
Example 4: (Rounding numbers)
Round each number to the nearest hundred.
a) 762
b) 981
c) 9732
Example 5: (Rounding numbers)
Round each number to the nearest thousand.
a) 78; 429
b) 11; 388
c) 9732
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Notes by Bibiana Lopez