standard_description: Apply properties of operations as strategies to multiply and divide. (Students need not use formal terms for these properties.) ^( )Examples: If 6 × 4 = 24 is known, then 4 × 6 = 24 is also known. (Commutative property of multiplication.) 3 × 5 × 2 can be found by 3 × 5 = 15, then 15 × 2 = 30, or by 5 × 2 = 10, then 3 × 10 = 30. (Associative property of multiplication.) Knowing that 8 × 5 = 40 and 8 × 2 = 16, one can find 8 × 7 as 8 × (5 + 2) = (8 × 5) + (8 × 2) = 40 + 16 = 56. (Distributive property.)
problem_activity: Problem 1
For each of the following problems,
Decide if it can be solved using multiplication or division. Explain your thinking.
For each word problem that can be solved using multiplication or division, represent it using an equation with a letter standing for the unknown quantity.
Solve.
a.   Nadeem is reading a book. It takes him 7 minutes to read each page. How many minutes will it take for Nadeem to read 10 pages?
b.   Helen spent some money on her 3 grandchildren at the fair. If she spent a total of $12, how much did she spend on each grandchild?
c.   Kiara is making saris. She has 30 meters of fabric and needs 5 meters to make each sari. How many saris can Kiara make?
Problem 2
For each part below, write a word problem that can be represented with the given expression.
a.
$$4 \times 6$$
b.
$$15 \div 3$$


aligns: no