options: Apply and extend previous understandings of multiplication to multiply a fraction or whole number by a fraction.

Solve real world problems involving multiplication of fractions and mixed numbers, e.g., by using visual fraction models or equations to represent the problem.

Interpret a fraction as division of the numerator by the denominator (a/b = a ÷ b). Solve word problems involving division of whole numbers leading to answers in the form of fractions or mixed numbers, e.g., by using visual fraction models or equations to represent the problem. For example, interpret 3/4 as the result of dividing 3 by 4, noting that 3/4 multiplied by 4 equals 3, and that when 3 wholes are shared equally among 4 people each person has a share of size 3/4. If 9 people want to share a 50-pound sack of rice equally by weight, how many pounds of rice should each person get? Between what two whole numbers does your answer lie?

Interpret multiplication as scaling (resizing), by:
- Explaining why multiplying a given number by a fraction greater than 1 results in a product greater than the given number (recognizing multiplication by whole numbers greater than 1 as a familiar case); explaining why multiplying a given number by a fraction less than 1 results in a product smaller than the given number; and relating the principle of fraction equivalence a/b = (n×a)/(n×b) to the effect of multiplying a/b by 1.
- Comparing the size of a product to the size of one factor on the basis of the size of the other factor, without performing the indicated multiplication.

Apply and extend previous understandings of division to divide unit fractions by whole numbers and whole numbers by unit fractions. (Students able to multiply fractions in general can develop strategies to divide fractions in general, by reasoning about the relationship between multiplication and division. But division of a fraction by a fraction is not a requirement at this grade.)
problem_activity: Problem 1
Jenny buys 2 feet of string. If this is one-third the amount she needs to make a bracelet, how many feet will she need?
a.   Draw a diagram to represent the problem.
b.   Write an expression to represent the problem.
c.   Find how many feet of string Jenny needs.
Problem 2
a.   Match each division expression (cut out from
Template: Fraction Division Sort
) with a situation (cut out from
Template: Fraction Division Sort
). Some expressions do not have a matching situation.
b.   Answer each question. Be prepared to share your reasoning.
Problem 3
a.   Write a story context that can be solved using the expression
$${2\div{1\over4}}$$
.
b.   Write a story context that can be solved using the expression
$${{1\over3}\div4}$$
.


correct_option_index: 4