Transcript Comparing Rational Numbers

Activator
• Compare: Which is more of a dollar?
5 dimes and 3 pennies to 17/34
How do you compare rational numbers
using inequality symbols?
• Name the inequality symbol
<
Less Than
>
Greater Than
Comparing Rational Numbers
1. Make sure all numbers are in the same
form
My suggestion would be to turn all numbers
into decimals. It is easier to compare
decimals than fractions with different
denominators.
Using the Calculators
• On the next two slides you will see ways to
change fractions to decimals and decimals
to fractions.
• If you already know how to do this then
you do not need to copy, but if you don’t
you will want to copy the notes.
• I do want you to try both methods on each
slide with a calculator.
Using the Calculator
• Turning a fraction to a decimal (2 ways)
1.One way to turn a fraction into a decimal is
simply divide the numerator by the
denominator.
2.The other way is to use the F to D button.
To use type in the fraction as follows.
Numerator, A b/c button, denominator, 2nd
key, PRB button (above it will have in
yellow, F < >D.
Using the Calculator
• Turning a decimal to a fraction (2 ways)
1.One way to turn a decimal into a fraction is to
write the decimal number (minus the
decimal), A b/c button, place value of the last
digit. Push equal and it should simplify if it
can.
Example: 0.325 = 325/1000 = 13/40
2. The other way is to use the F to D button.
Type in the decimal, 2nd key, PRB (in yellow
above it is F<>D), equal button.
Placing and Comparing Using Number
Lines
• The key with number lines is to know how the
number line is divided.
• To determine how the number line is divided
you simply count the number of marks
between two marked numbers.
• If it is broken into sets of ten then you can
use a decimal number.
• If it is broken into any other set of numbers
then you are using a fraction. Some fractions
can easily be changed to decimals if needed.
Example ¼ can be turned into .25
Ordering Rational Numbers
• Order -1, -1.6, 2/5, 1 ¼, and -3/8 from
least to greatest.
Ordering Rational Numbers
• Order -1, -1.6, 2/5, 1 ¼, and -3/8 from
least to greatest.
– How do I order these?
– All numbers MUST be in the same form!
Option 1
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Find the rational numbers of each value.
Find an LCD and create equivalent fractions.
Order from least to greatest.
Place values back into original form.
Option 2
Convert all numbers to decimals.
Order from least to greatest.
Place Numbers back into original form.
On Your Own
Order from least to greatest using rational
numbers:
a) 2.5, -1, -5/8, -0.8
b) 4 1/5, -3.6, -3 8/9, 0
Comparing and Ordering Decimals
Tenths Number Line
Hundredths Number line
Thousandths Number line