multiplying decimals & properties of multiplication christine berg edited by v t hamilton
TRANSCRIPT
Multiplying Multiplying Decimals &Decimals &Properties of Properties of MultiplicationMultiplication
Christine BergChristine BergEdited By V T HamiltonEdited By V T Hamilton
Step 1Step 1::Multiply as if the Multiply as if the
factors were whole factors were whole numbers numbers
Step 1Step 1:: 8.58.5
X2.5X2.5
4 2 54 2 5
1 7 0 01 7 0 0
2 1 2 5 next…..2 1 2 5 next…..
Step 2Step 2::
Count the total Count the total decimals places in decimals places in
the factorsthe factors
Step 1Step 1:: 8.8.55
X2.X2.5 5
4 2 54 2 5
1 7 0 01 7 0 0
2 1 2 5 next…..2 1 2 5 next…..
Step 3Step 3::
Give the product Give the product the total decimal the total decimal
places of the places of the factorsfactors
Step 1Step 1:: 8.8.55
X2.X2.5 5
4 2 54 2 5
1 7 0 01 7 0 0
2 1 2 1 .2 5.2 5
Try These:Try These:
1. 4.8 2. 3.55 x 0.5 x .05
Answers:Answers:
1. 4.8 2. 3.55 x 0.5 x .05
= 2.40 = 0.1775
Properties of Properties of MultiplicationMultiplication
Identity PropertyIdentity Property
The product of 1 and The product of 1 and a number (a number (aa) is the ) is the
number (number (aa))
1(a) = a1(a) = a
ExamplesExamples
1 (b) = b1 (b) = b
1 x 42 = 421 x 42 = 42
Zero PropertyZero Property
The product of 0 and The product of 0 and a number (a number (aa) is 0) is 0
0 (a) = 00 (a) = 0
ExamplesExamples
0 (b) = 00 (b) = 0
0 x 67 = 00 x 67 = 0
Commutative Commutative PropertyProperty
Changing the order Changing the order of the factors does of the factors does
not change the not change the answeranswer
ExamplesExamples
a ( b ) = b ( a )a ( b ) = b ( a )
5 x 2 = 2 x 55 x 2 = 2 x 5
Associative Associative PropertyProperty
Changing the Changing the grouping of factors grouping of factors does not change does not change
the answerthe answer
ExamplesExamples(( a a bb ) ) cc = = aa ( ( bb cc ) )
( 3 x 2 ) x 4 = 3 x ( 2 x 4 )( 3 x 2 ) x 4 = 3 x ( 2 x 4 )
Try These:Try These:Identify the propertyIdentify the property
(( x y x y ) z = ) z = xx ( ( yy zz ) )
0 x 4 = 00 x 4 = 0
Answers:Answers:(( x y x y ) z = ) z = xx ( ( yy zz ) )
Associative Property of xAssociative Property of x
0 x 4 = 00 x 4 = 0
Zero PropertyZero Property