4) Fractions: Multiply x Fractions or Whole Numbers
5.NF.B.4 (A & B)
5.NF.B.4 (A & B)
I can use what I know about multiplication to multiply fractions or whole numbers by a fraction.
A) I can understand and show with models that multiplying a fraction by a whole number is the same as finding the product of the numerator and whole number and then dividing it by the denominator. 2 × 6 = 2 + 2 + 2 + 2 + 2 + 2 = 12 3 3 3 3 3 3 3 3 12 = 3 + 3 + 3 + 3 = 3 + 3 + 3 + 3 = 4 3 3 3 3 3 3 Check your work using the algorithm: 2 × 6 = 2 × 6 = 12 = 12 ÷ 3 = 4 3 3 × 1 3 Video: Multiply Fractions & Whole Numbers Video: Multiply Fractions by whole numbers on a number line Practice: Multiply Fractions & Whole Numbers 2 = 2 × 1 = 1 + 1 5 5 5 5 3 × 2 = 3 × 2 × 1 = (3 × 2) × 1 = 6 × 1 5 5 5 5 Video: Multiply Fractions & Whole Numbers Visually Practice: Multiply Fractions & Whole Numbers Visually Find the product of a whole number and a fraction by using area models. (LearnZillion) B) I can use unit squares to find the area of a rectangle with fractional side lengths and prove that it is the same as multiplying the side lengths (where A = Area, l = length, w = width, to find the area, A = l x w). Video: Multiply Unit Fractions and Whole Numbers Video: Finding Area with Fractional Sides (1) (e.g. a rectangle whose sides' measures include a fraction, like the length = 7/8 ft. and width = 5/9 ft. ) Video: Finding Area with Fractional Sides (2) Practice: Areas of Rectangles with Fraction Side Lengths |
If you would like to read the CA State Standards:
Big Idea: Apply and extend previous understandings of multiplication and division to multiply and divide fractions. 4. Apply and extend previous understandings of multiplication to multiply a fraction or whole number by a fraction. a.Interpret the product (a/b) × q as a parts of a partition of q into b equal parts; equivalently, as the result of a sequence of operations a × q ÷ b. For example, use a visual fraction model to show (2/3) × 4 = 8/3, and create a story context for this equation. Do the same with (2/3) × (4/5) = 8/15. (In general, (a/b) × (c/d) = ac/bd.) b.Find the area of a rectangle with fractional side lengths by tiling it with unit squares of the appropriate unit fraction side lengths, and show that the area is the same as would be found by multiplying the side lengths. Multiply fractional side lengths to find areas of rectangles, and represent fraction products as rectangular areas. |