Fractions are parts of a whole' If an amount is divided into equal parts, or fair shares, we can und - PowerPoint PPT Presentation

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Fractions are parts of a whole' If an amount is divided into equal parts, or fair shares, we can und

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The simpler fraction has smaller numbers in the numerator and the denominator ... To add two like mixed numbers, you take three steps: ... – PowerPoint PPT presentation

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Title: Fractions are parts of a whole' If an amount is divided into equal parts, or fair shares, we can und


1
  • Fractions are parts of a whole. If an amount is
    divided into equal parts, or fair shares, we can
    understand and name the fractions.
  • There are three questions we need to answer to
    understand what any fraction really means.
  • The first question is, What is the whole and how
    big is it? The context of the fraction answers
    this question.

Gr4-U8-L1
2
  • Fractions are parts of a whole. If an amount is
    divided into equal parts, or fair shares, we can
    understand and name the fractions.
  • There are three questions we need to answer to
    understand what any fraction really means.
  • The first question is, What is the whole and how
    big is it? The context of the fraction answers
    this question.

Gr4-U8-L1
3
  • The second question is, Into how many equal
    parts has the whole been divided? The
    denominator of the fraction answers this
    question.
  • The third question is, How many of the equal
    parts are we using? The numerator of the
    fraction answers this question.

Gr4-U8-L1
4
  • Equivalent fractions describe the same portion of
    a whole divided in different ways. In other
    words, different fractions that name the same
    portion of a whole are called equivalent
    fractions. For example, a half of a piece of
    paper can be represented as 1/2, 2/4, 3/6, 4/8,
    or 5/10 of the piece of paper, and so on.

Gr4-U8-L2
5
  • To find an equivalent fraction, you multiply the
    numerator and the denominator of your fraction by
    the same number. For example, 1/2 4/8 because
    both the numerator and the denominator are
    multiplied by 4.

Gr4-U8-L3
6
  • Any number multiplied by 1 equals itself. When
    we multiply the numerator and the denominator by
    the same number, it is like multiplying by 1, so
    the product is equal to the original fraction.

Gr4-U8-L3
7
  • We find a simpler equivalent fraction for a
    fraction by grouping many small parts into a few
    big parts. The simpler fraction has smaller
    numbers in the numerator and the denominator and
    is easier to understand. For example, 3/4 is
    easier to understand than 12/16.

Gr4-U8-L4
8
  • Any number divided by 1 equals itself. When we
    divide the numerator and the denominator by the
    same number, it is like dividing by 1, so the
    quotient is equal to the original fraction.

Gr4-U8-L5
9
  • To simplify a fraction you find an equivalent
    fraction with smaller numbers by dividing the
    numerator and the denominator of the fraction by
    the same number. For example, 8/12 2/3 because
    both the numerator and the denominator are
    divided by 4.

Gr4-U8-L5
10
  • Fractions can be ordered on a number line just as
    whole numbers can be ordered.
  • Proper fractions are fractions in which the
    numerator is less than the denominator. For
    example, 1/2 is a proper fraction but 3/2 is not.
  • Positive proper fractions are greater than 0 and
    less than 1, so they are found between 0 and 1 on
    the number line.

Gr4-U8-L6
11
  • Like fractions have the same denominator. For
    example, 3/4 and 2/4 are like fractions.
  • When we compare like fractions, we just compare
    the numerators because the denominators are the
    same. For example, when we compare 3/4 and 2/4,
    we say that 3 is more than 2 because both
    fractions are fourths.

Gr4-U8-L6
12
  • Unlike fractions have different denominators.
    For example, 3/4 and 2/3 are unlike fractions.
  • To find a common denominator for two unlike
    fractions, we can multiply the denominators. For
    example, 3/4 and 2/3 have a common denominator of
    12.

Gr4-U8-L7
13
  • To compare unlike fractions, we find equivalent
    fractions with a common denominator and then
    compare the numerators. For example, when we
    compare 3/4 and 2/3, we say 3/4 9/12 and 2/3
    8/12, and 9/12 gt 8/12, so 3/4 gt 2/3.

Gr4-U8-L7
14
  • A mixed number is a number that includes a whole
    number and a proper fraction. For example, 21/2
    represents 2 wholes and 1/2 of another whole
  • An improper fraction is a fraction with a
    numerator equal to or greater than the
    denominator. For example, 5/2 is more than 1
    whole since 2/2 1.

Gr4-U8-L8
15
  • To change a mixed number to an improper fraction,
    you change each whole in the whole number to a
    fraction with the same denominator as the
    fractional part of the mixed number, and add all
    the fractions together. For example, 31/4 4/4
    4/4 4/4 1/4 13/4.

Gr4-U8-L9
16
  • To change an improper fraction to a mixed number,
    you make sets of the fractions each equal to 1
    whole, count the sets to find the number of
    wholes, and put that with the fraction that is
    left over. For example, 13/4 - 4/4 9/4, 9/4 -
    4/4 5/4, 5/4 - 4/4 1/4. 4/4 4/4 4/4
    1/4 31/4.

Gr4-U8-L10
17
  • To change an improper fraction to a mixed number,
    you divide the denominator into the numerator to
    find how many wholes there are and how many parts
    are left over. For example, 20/8 sixteen-inch
    pizzas 20 ? 8 2 R4, so 20/8 pizzas 24/8
    sixteen-inch pizzas.

Gr4-U8-L10
18
  • All whole numbers and mixed numbers can be
    written as improper fractions. All improper
    fractions can be written as either whole numbers
    or mixed numbers.

Gr4-U8-L10
19
  • We can estimate that fractions are close to 1/2
    by seeing if their denominators are about twice
    as much as their numerators. For example, in
    7/12 the 12 is almost twice as much as the 7, so
    7/12 of a sheet cake is about 1/2 of the cake.

Gr4-U8-L11
20
  • If a fraction is a very small part of a whole,
    the fraction is close to 0. For example, 1/12 is
    a very small part of 12/12, so 1/12 of a sheet
    cake is almost no cake at all.

Gr4-U8-L11
21
  • If the numerator is almost the same size as the
    denominator, the fraction is close to 1. For
    example, in 11/12, the 11 is almost as big as the
    12 and 11/12 of a sheet cake is almost the whole
    cake.
  • Comparing a fraction to 0, 1/2, or 1 helps us
    estimate amounts or interpret data in a
    meaningful way.

Gr4-U8-L11
22
  • Adding like fractions is just like adding
    anything else. For example, 3 children 2
    children 5 children, so 3 eighths 2 eighths
    5 eighths.

Gr4-U8-L12
23
  • To add like fractions, we add the numerators and
    put the sum over the denominator. The
    denominator doesnt change, because the size of
    each piece doesnt change we just have more
    pieces. For example, 3/8 2/8 5/8 of a piece
    of paper. We still have eighths there are just
    more of them.

Gr4-U8-L12
24
  • To add unlike fractions, find equivalent
    fractions with a common denominator, add the
    numerators, and put the sum over the common
    denominator. For example, 2/5 1/2 4/10
    5/10 9/10 of a piece of paper.

Gr4-U8-L12
25
  • Amounts greater than 1 can be represented in many
    different ways. For example, 23/4 pies can be
    represented as 53/4 pies or 47/4 pies or 4 13/4
    pies.

Gr4-U8-L13
26
  • To add two like mixed numbers, you take three
    steps
  • 1. Add the fractions and add the whole numbers.
  • 2. If the sum of the fraction part of the mixed
    numbers is an improper fraction, change it to a
    whole or mixed number.
  • 3. Add the wholes and simplify the answers if
    appropriate.

Gr4-U8-L14
27
  • To add two unlike mixed numbers, you take four
    steps
  • 1. Change to equivalent like fractions.
  • 2. Add the fractions and add the whole
    numbers.
  • 3. If the sum of the fraction part of the
    mixed numbers is an improper fraction, change
    it to a whole or mixed number.
  • 4. Add the wholes and simplify the answers if
    appropriate.

Gr4-U8-L14
28
  • To subtract like fractions, we subtract the
    numerators and put the difference over the
    denominator. The denominator doesnt change,
    because the size of each piece doesnt change we
    just have fewer pieces. For example, 5/8 - 2/8
    3/8 of a piece of paper. We still have eighths
    there are just fewer of them.

Gr4-U8-L15
29
  • Subtracting like fractions is just like
    subtracting anything else. For example, 5
    children - 2 children 3 children, so 5 eighths
    - 2 eighths 3 eighths of a piece of paper.

Gr4-U8-L15
30
  • To subtract unlike fractions, find equivalent
    fractions with a common denominator, subtract the
    numerators, and put the difference over the
    common denominator. For example, 5/6 - 1/2
    10/12 - 6/12 4/12, or 1/3, of an eight-inch pie.

Gr4-U8-L15
31
  • To subtract two like mixed numbers when the
    larger number also has the larger fraction, you
    take three steps
  • 1. Subtract the Fractions.
  • 2. Subtract the whole numbers.
  • 3. Simplify the answer if appropriate.

Gr4-U8-L16
32
  • To subtract two unlike mixed numbers when the
    larger number also has the larger fraction, you
    take four steps
  • 1. Change to equivalent like fractions.
  • 2. Subtract the Fractions.
  • 3. Subtract the whole numbers.
  • 4. Simplify the answer if appropriate.

Gr4-U8-L16
33
  • To subtract two mixed numbers, you take five
    steps
  • 1. Check the fractions and change to
    equivalent like fractions if necessary.
  • 2. Compare the fractions and regroup 1 whole
    in the larger number.
  • 3. Subtract the Fractions.
  • 4. Subtract the whole numbers.
  • 5. Simplify the answer if appropriate.

Gr4-U8-L17
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