Multiplying Rational Numbers
The product of two rational numbers is the product of the numerators divided by
the
product of the denominators.
Reduce the product .
Reduced this will be
Dividing Rational Numbers
If the product of a and b is one, then a
and b are reciprocals.
and
are reciprocals
5 and 
are
reciprocals
and
are reciprocals
The quotient of two rational numbers is found by
multiplying by the reciprocal .
Reduce the product.
Reduced this will be
Adding Rational Numbers
To add two rational numbers that have the same
denominator, add the numerators
and write the sum over the denominator.
Reduce the sum.
Reduced this will be
Playing with blocks can help us understand addition of
fractions .
To add two rational numbers that have the different
denominators , write the rational
numbers as equivalent fractions with the same denominators (The smallest
possible
denominator will be the LCM of the two denominators) then add the numerators
and write the sum over the denominator.
It is always true that 
bd is not necessarily the smallest denominator but it will
work.
Subtraction is the same as addition.
The rational numbers are dense. Between any two rational
numbers there is another
rational number.
To find a rational number that is half way between two other rational numbers,
add
them together and divide by 2 (find the average.) Multiplying by one half is the
same
as dividing by two.
What number is half way between
and 
is half way between
and
A chocolate chip cookie recipe for 3 dozen
cookies requires ⅔ of a cup of sugar. How
many cups of sugar will be required to
bake 8 dozen cookies?
A chocolate chip cookie recipe for 3 dozen
cookies requires 4 eggs. How many eggs
will be required to bake 8 dozen cookies? |
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