Remarks
Remarks: The use of multiple strategies might incorporate number properties for both multiplication and division including the commutative property, associative property, distributive property, and the identity property. The zero property of multiplication may also be used to solve problems.
A problem such as 8 x 6 can be solved by finding 4 x 6 then doubling the product. This strategy uses the associative property in that 8 x 6 = 2 x (4 x 6).
The distributive property is applied to 7 x 8 when we find 5 x 8 and add it to 2 x 8. Hence, 7 x 8 = (5 + 2) x 8 = (5 x 8) + (2 x 8).
Consider the following solution using the distributive property as a mental math strategy. Given 14 x 5 we may conclude (10+4) x 5= (10 x 5) + (4 x 5) = 50 + 20 = 70.
Another application of a mental math strategy using the distributive property may lead one to conclude 19 x 5 = (20 -1) x 5 = (20 x 5) - (5 x 1) = 100 - 5 = 95.
Example: Sally and Thomas each have a $5 bill and three $1 bills to spend at the book fair. Together the total amount of money they have can be shown using the expression below.
2 x (3 + 5)
Write a different expression that represents the total amount that Sally and Thomas have together. How much money do they have altogether?
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Item Type(s):
This benchmark may be assessed using:
MC
item(s)
- Clarification :
Students will recognize equivalent representations of equations or expressions by using number properties, including the commutative, associative, distributive, and identity properties for multiplication and division and the zero property of multiplication. - Content Limits :
Items will not include identifying the properties by name.Items will not require the use of more than two properties to convert one expression or equation to its equivalent.
Items may include only factors or divisors of 0 through 9.
- Stimulus Attributes :
Items may be set in either a real-world or mathematical context.
- Test Item #: Sample Item 1
- Question:
Raymond has 5 pictures of each of 3 types of ocean dolphins. He also has 4 pictures of river dolphins. The expression below represents the total number of dolphin pictures Raymond has.
(3 x 5) + 4
Which expression below also represents the total number of dolphin pictures Raymond has?
- Difficulty: N/A
- Type: MC: Multiple Choice