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    • ▾5th grade
      • ▸Decimal place value
        • •Decimal place value
        • •Hashi puzzles
        • •Decimals to thousandths
        • •Rounding decimals
      • ▸Multi-digit multiplication and division
        • •Multiplying whole numbers by 10, 100, and 1000
        • •Multiplying and dividing decimals by 10, 100, and 1000
        • •Convert fractions to decimals, 10, 100, or 1000 in the denominator
        • •Multiplication, partial products method
        • •Long division
      • ▸Decimal arithmetic
        • •Decimal arithmetic
        • •Dividing whole numbers to get a decimal
      • ▸Add and subtract fractions
        • •Add and subtract fractions, abstract
        • •Adding and subtracting mixed numbers with regrouping
        • •Add and subtract fractions, word problems
      • ▾Multiply fractions
        • •Multiplication as scaling
        • •Areas and perimeters, fractional side lengths
        • •Multiply fractions, abstract
        • •Multiply fractions, word problems
      • ▸Divide fractions
        • •Understanding fractions as division, word problems
        • •Dividing whole numbers by unit fractions
        • •Dividing unit fractions by whole numbers
        • •Dividing mixed numbers
      • ▸Volume
        • •Volume by counting unit cubes
        • •Volume of right rectangular prisms by multiplying
        • •Volume of composite right rectangular prisms
        • •Volume, word problems
      • ▸Coordinate plane
        • •Plot coordinates
        • •Plot coordinates from word problems
      • ▸Algebraic thinking
        • •Intro to parentheses
        • •Distributive property without variables
        • •Convert between words and arithmetic expressions
        • •Linear equations, tables
      • ▸Measurement and data
        • •Unit conversion
        • •Represent and reason with line plots
      • ▸Properties of shapes
        • •Geometric definitions
        • •Classifying shapes
        • •Classifying triangles
        • •Classifying polygons
        • •Symmetries of regular polygons
        • •Quantifiers
     › 5th grade › Multiply fractions

    Areas and perimeters, fractional side lengths

    Students will learn how to find the area and perimeter of a rectangle with fractional side lengths.

    Watch these Khan Academy videos:

    • Finding area with fractional sides 1
    • Finding area with fractional sides 2

    Area of rectangles with fraction side lengths by Khan Academy

    Next, give your students these challenges:

    • 2018 Math Kangaroo Levels 5-6 Problem #19 by STEM4all

    Ten red socks and ten blue socks are all mixed up in a dresser drawer. The twenty socks are exactly alike except for their color. The room is in pitch darkness and you want two matching socks. What is the smallest number of socks you must take out of the drawer in order to be certain that you have a pair that match? This puzzle comes from Gardner's Entertaining Mathematical Puzzles.

    If students cannot figure it out, act out the problem as a class. For example, you could have a bag of twenty marbles, ten white and ten black. Have students draw from the bag until they get a matching pair. Running this experiment a few times, they will see maximum number of draws necessary is three. Then you can explain why.

    Conclude by leading this investigation:

    1-100 Composite Connector Challenge
    by MathPickle

    5.NF.B.4: Apply and extend previous understandings of multiplication to multiply a fraction or whole number by a fraction.