DECIMALS

                                   DECIMALS

Decimal Notes Math SOL 4.4 a

Reading Decimals

·        “A decimal point separates the whole number from the places that are less than one.

·        Place values extend infinitely in two directions from a decimal point.

·        A number containing a decimal point is called a decimal number or simply a decimal.”

·        If, the whole illustration below equals one. How much do the shaded sections equal?

1.

2.

3.

Hundreds	Tens	Ones	Decimal Point	Tenths	Hundredths	Thousandths
8	4	1	.	5	6	2

Reading a number into the decimals

1.   Say the first part (left of the decimal) of the number like normal.  (if there is one)

2.   Say “and” where the decimal is.

3.   Say the second part of the number like normal but end with the last/smallest place value

Example: eight hundred forty one AND five hundred sixty two thousandths

Practice:

1.   485.856 -

2.   1835.21 –

3.   881.584 –

4.    684.9 –

5.    38.358 –

Decimal Notes Math SOL 4.4 a

Writing Decimals

Writing Decimals can be written in standard, written, or expanded forms.

Standard - # form

·        0.2

·        0.85

·        2.376

·        315.007

Written = word form

·        Two tenths

·        Eighty-five hundredths

·        Two and three hundred seventy-six thousandths

·        Three hundred fifteen and seven thousandths

Expanded = equation form broken up by place values.

·        (0 x 1) + (2 X .1)

·        (0 x 1) + (8 x .1) + (5 x .01)

·        (2 x 1) + (3 x .1) + (7 x .01) + (6 x .001)

·        (3 x 100) + (1x 10) + (5 x 1) + (0 x .1) + (0 x .01) + (7 x .001)

Rounding Decimals Math SOL 4.4 b

Rounding decimals is the same as rounding any other whole number.

1.   Look to where you are being asked to round.

2.   Then look to the number on the right.

a.   5 or higher round up

b.   4 or less leave it alone & drop all the digits to the right of the rounded place value

3.   Say your number stopping at the rounded place value.

Example/Practice:

1.   Round 0.876 to the nearest hundredths = .88

2.   Round 1.23 to the nearest tenths =

3.   Round 32.056 to the nearest hundredths =

4.   Round 157.098 to the nearest tenths =

5.   Round 5.752 to the nearest hundredths =

Comparing Decimals Notes Math SOL 4.4 c

> - greater than

<  - less than

 =  - equal to

Comparing decimals is similar to comparing whole numbers.

Look at the highest place value available and figure out which number is larger.

Examples:

·        0.86 ___ .65    greater than or >

·        1.038 ___ .0038

·        3.248 ___ 3.258

·        7.2 ___ 7.9

·        5.24 ___ 5.34

·        6.07 ___ 6.7