WHOLE NUMBER MULTIPLICATION
PROPERTIES, 1-DIGIT AND 2-DIGIT MULTIPLICATION, PROBLEM SOLVING
As in addition, the multiplication properties help organize multi-step math problems. By following the properties, problems may be reordered and regrouped to solve the problem mentally.
The distributive property is used to distribute multiplication over a sum of numbers. We will look at how a multiplication problem can be completed using the distributive property and mental math.
In multiplication, we find the product. First, we’ll look at multiplying by multiples of ten and by a single digit. Next, we’ll find the product of two numbers where we are multiplying by a 2-digit number.
We will apply multiplication to word problems. Look for key words and read the problem more than once.
Multiplication Properties Commutative, Associative, Identity, Zero Use the commutative, associative, identity, and zero properties to simplify.
Example 1
Steps Reasons (2 × 9) × 25 Commutative Property 2 × 9 = 9 × 2 (9 × 2) × 25 Associative Property 9 × (2 × 25) Multiply 2 × 25 to get 50 9 × 50 = 450
Example 2
Steps Reasons 7 × 1 × 0 Identity Property (7 × 1 = 7) 7 × 0 Zero Property (7 × 0 = 0) 0 |
Distributive Property
The distributive property is used to distribute multiplication over a sum of numbers. Look to see how a multiplication problem can be completed using the distributive property and mental math.
Study the statements and reasons below to solve the given problem using the distributive property. |
Whole Number Multiplication – One Digit Numbers
Look at the pattern below.
8 × 3 = 24 80 × 3 = 240 800 × 3 = 2400 8000 × 3 = 24,000
Notice that a shortcut would be to multiply the 8 × 3, then count the number of zeros and add them on.
Estimate the product, then solve: 7342 × 6
Estimation: 7000 × 6 = 42,000 The estimated answer is 42,000. Solution: Line up the numbers from right to left.
Check: The estimated answer, 42,000, is close to 44.052. |
Whole Number Multiplication – Two Digit Numbers
Estimate the product, then solve: 637 × 48
Estimation: 600 × 50 = 30,000 The estimated answer is 30,000.
Solution: Line up the numbers from right to left. Answer: 637 × 48 = 30,576
Check: The estimated answer, 30,000, is close to 30,576. |
Problem Solving - Multiplication
The computer club is planning to attend a baseball game. There are 26 members in the club and each ticket to the game costs $12.50. How much would the tickets cost?
In this problem you know the cost of one and want to find the cost of 26. This is a multiplication problem.
26 × 12.50 = $325.00 |
 Multiplication |
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