Multiplication. Mrs. Walker 4 th Grade. Objective:. Today will learn how to multiply numbers with 2 digits by numbers with 1 digit. Example: . 34 x 9. Why do we need to know the Multiplication Properties?. It helps you solve problems without working them out. - PowerPoint PPT Presentation
Multiplication Properties
MultiplicationMrs. Walker 4th GradeObjective:Today will learn
how to multiply numbers with 2 digits by numbers with 1 digit.
Example:
34x 9Why do we need to know the Multiplication Properties?It
helps you solve problems without working them out.It helps with
mental math.It makes understanding math easier.
Vocabulary To Know:FactorProductCommutative PropertyAssociative
PropertyIdentity PropertyZero PropertyDistributive
PropertyFactorThe numbers that are multiplied together in a
multiplication problem.
Example:
34 x 9 = 306ProductThe answer to a multiplication problem.
Example:
34 x 9 = 306Commutative Property of MultiplicationThe order that
factors (numbers) are multiplied will not change the product
(answer).
Example:
56 x 4 = 4 x 56Commutative Property of MultiplicationLets
Practice:34 x 8 = ____ x 345 x ____ = 62 x 5____ x 9 = 9 x
71Associative Property of MultiplicationThe way that factors
(numbers) are grouped will not change the product (answer).
Example:
(21 x 3) x 9 = 21 x (3 x 9)Associative Property of
MultiplicationLets Practice:34 x (___ x 6) = (34 x 8) x 6(431 x 6)
x 3 = ___ x (6 x 3)19 x (___ x ___) = (19 x 2) x 7
ZeroProperty of MultiplicationAny factor (number) multiplied by
0 will equal 0.
Example:
679 x 0 = 0ZeroProperty of MultiplicationLets Practice:43 x 0 =
____ 35 x ____ = 0IdentityProperty of MultiplicationAny factor
(number) multiplied by 1 will equal that number.
Example:
679 x 1 = 679IdentityProperty of MultiplicationLets Practice:55
x 1 = ____ 77 x ____ = 77Distributive Property of
MultiplicationWhen two addends are multiplied by a factor the
product will be the same as when each addend is multiplied by the
factor and the products are added.
Example:
(2 + 3) x 4 = (2 x 4) + (3 x 4)Distributive Property of
MultiplicationLets Practice:(2 + 6) x 34 = (___ x 34) + (___ x
34)(6 + 9) x 16 = (___ x 16) + (___ x 16)(4 + 5) x 23 = (4 x ___) +
(5 x ___)(___ + 3) x 11 = (7 x 11) + (3 x 11)(___ + ___) x 90 = (4
x 90) + (1 x 90)
Multiplication StepsWrite the problem lining up the place values
(ones under ones).Multiply the bottom number in the ones place by
the top number in the ones place. Write the answer below the
problem in the ones place. Regroup if necessary.Multiply the bottom
number in the ones place by the top number in the tens place and
add the number you carried if you have one.Write the answer below
the problem in the tens place.
2 Digit x 1 Digit2 Digit x 1 DigitStart Here212 Digit x 1
Digit52121016Hand Trick:
UP then OVER!2 Digit x 1 Digit42136212 5Hand Trick:
UP then OVER!2 Digit x 1 Digit72199366 9Hand Trick:
UP then OVER!You Try One62148425 0You Try Another891271 591392
7You Try Another3 Digit x 1 Digit52101621 0112,333 Digit x 1
Digit39372161 9112,331Independent Practice14 x 5 =62 x 2 =234 x 9
=45 x 7 =87 x 4 =
28 x 1 =26 x 3 =343 x 6 =54 x 8 =414 x 3 =
2 & 3 Digit x 1 Digit2 Digit x 2 Digit StepsStart
Here210Start Here21Step 1: Write the problem making sure you line
up the correct place values.Step 2: Do the green steps first.Step
3: Mark out the number you carried and add a zero to hold the ones
place.Step 4: Do the red steps next.Step 5: Add the green and red
answers together.Hand Trick:
UP then OVER and OVER then UP!
12 Digit x 2 Digit21021Step 1: Write the problem making sure you
line up the correct place values.Step 2: Do the green steps
first.Step 3: Mark out the number you carried and add a zero to
hold the ones place.Step 4: Do the red steps next.Step 5: Add the
green and red answers together.462381 3219851 0,Hand Trick:
UP then OVER and OVER then UP!
2 Digit x 2 Digit21021Step 1: Write the problem making sure you
line up the correct place values.Step 2: Do the green steps
first.Step 3: Mark out the number you carried and add a zero to
hold the ones place.Step 4: Do the red steps next.Step 5: Add the
green and red answers together.835261 6514 1613,14Hand Trick:
UP then OVER and OVER then UP!
32 Digit x 2 Digit0Step 1: Write the problem making sure you
line up the correct place values.Step 2: Do the green steps
first.Step 3: Mark out the number you carried and add a zero to
hold the ones place.Step 4: Do the red steps next.Step 5: Add the
green and red answers together.943827 5212 8275,31Hand Trick:
UP then OVER and OVER then UP!
22 Digit x 2 Digit0Step 1: Write the problem making sure you
line up the correct place values.Step 2: Do the green steps
first.Step 3: Mark out the number you carried and add a zero to
hold the ones place.Step 4: Do the red steps next.Step 5: Add the
green and red answers together.852554 2011 7521,211You try one0Step
1: Write the problem making sure you line up the correct place
values.Step 2: Do the green steps first.Step 3: Mark out the number
you carried and add a zero to hold the ones place.Step 4: Do the
red steps next.Step 5: Add the green and red answers together.23142
93222312You try another0Step 1: Write the problem making sure you
line up the correct place values.Step 2: Do the green steps
first.Step 3: Mark out the number you carried and add a zero to
hold the ones place.Step 4: Do the red steps next.Step 5: Add the
green and red answers together.734845 8212 9405,311Independent
Practice26 x 35 =62 x 41 =34 x 99 =45 x 74 =87 x 73 =
28 x 12 =26 x 37 =43 x 62 =54 x 86 =44 x 38 =
2 Digit x 2 DigitWhat do you think the steps will be to multiply
a 3 Digit x a 2 Digit?548x 19423x 25937x 623 Digit x 2 DigitGreat
Job!
