in this lesson you'll begin to learn
about fractions fractions are used to
describe the parts of whole units a
fraction is written like this in this
lesson you'll learn about the bottom
number of a fraction
to create a fraction we divide a whole
unit into equal parts
the bottom number of a fraction tells us
the number of equal parts in each whole
unit here's an example this box is one
whole unit we'll divide the box into four
equal parts
since the parts are equal each part is a
fraction of the whole unit there are
four equal parts in all so the bottom
number of each fraction is four
in this example there are three whole
units one two three
each whole unit is exactly the same size
when whole units are the same size we
can divide them into fractions each of
these whole units is still divided into
four equal parts
so the bottom number for any part or
fraction is the same as before four
here's another way of looking at the
equal parts of whole units or fractions
there are six whole units and each whole
unit is divided into two equal parts we
can put the whole units together like
this
each whole unit is now a line instead
of a box the tallest lines show the
beginning and end of each whole unit
we've just created a number line a
number line is another way to show
fractions which are just equal parts of
whole units
notice this arrow the arrow
on the number line you'll learn to write
the name for fractions like this for
this lesson you will only write the
bottom number of the fraction in this
example there are two equal parts in
each whole unit
so the bottom number for this fraction
is two here's a different fraction on
the same number line
each whole unit is still divided into
two equal parts so the bottom number for
this fraction is also 2
here's another example there are four
parts in each whole unit
so the bottom number for this fraction
is four the bottom number for this
fraction is also 4 and the bottom number
for this fraction is also 4 for any
fraction on this number line the bottom
number will always be 4 since each whole
unit has four equal parts
in the remainder of this lesson you'll
write the bottom number for the fraction
shown by the arrow on a number line like
these
