Lesson 4: Multiplication Flashcards
(4 cards)
You Will Learn:
* What Is Multiplication?
* What Are The Rules Of Multiplication?
* What Are Factors & Products?
* What Is Area?
* What Do You Multiply To Find The Area Of A Shape?
What Is Multiplication?
Multiplication Is What You Do When You Add A Number To Itself A Few Or Many Times. It’s A Quick Way Of Adding Several Of The Same Number.
You Probably Use It Without Thinking When You Measure And Count Things.
Multiplication Can Be Written With Different Symbols.
Example: 1x2 1*2 (1)(2)
The Word Times Is Used Often Instead Of Multiplied By.
Examples: 2 Multiplied By 2, Say “2 Times 2”
In These Math Lessons, We’ll Show Multiplication 2 Ways
1: We Use “X” To Show Multiplication.
Examples: 2x3=6 Means “2 Times 3 Equals 6”
How Does Multiplication Work?
Think Of MultiplicationAs Combining Groups Of The Same Size Into One Big Group.
The Table Below Has 5 Groups Of Colored Boxes With 3 Boxes In Each Group. If You Want To Combine Them To One Total, You Can Add 3+3+3+3+3 To Get 15.
Sky Blue Red Orange Blue Green
1 1 1 1 1
2 2 2 2 2
3 3 3 3 3
Or, You Can Multiply The 3 Boxes By 5 (5x3) Multiplying 3 By 5. Is The Same As Adding 3 To Itself 5 Times (3+3+3+3+3=15)
There Are 15 Boxes Total.
The Order Of Numbers Does Not Matter In Multiplication, The Same Problem Can Be Seen As 3 Groups Of 5 Boxes.
Multiplying 5x3 Is The Same As Adding 5 To Itself 3 Times (5+5+5). 5+5+5=15 There Are Still 15 Boxes Total. So 3x5 Is The Same As 5x3.
3 x 4 = 12
Factors Product
Factors & Products
The Numbers That Are Multiplied Are Called Factors. The Answer, Or Result, Is Called The Product.
Multiplication Rules
There Are A Few Multiplication Rules You Should Know. You May Know Most Of These, But If Not, You’ll Need To Memorize Them And Apply Them On Your Test.
- Any Number Multiplied By 0 Equals 0. It Becomes 0 Becasue 0 Times Any Number Says Theirs None Of That Number.
Examples: 0x4=0 3x0=0 (14)(21)(0)=0 - Any Number Multiplied By 1 Equals That Number. It Says The Same Because 1 Times Any Number Says It Is Only 1 Of That Number.
Examples: 25x1=25 (45)(1)=45 2/3x 1= 2/3
*A Positive Number Multiplied By A Negative Number Equals A Negative Number.
Examples: 3 x -4 = -12 -4 x 6 = -24 - A Negative Number Multiplied By A Negative Number Equals A Positive Number.
Examples: -3 x -3 = 9 (-5)(-5) = 25 - We Already Learned The Last Rule: You Can Multiply Numbers In Any Order. The Order Of Multiplying Does Not Change The Answer.
Examples: 3 x 6 =18 6 x 3 =18 (4)(2)(2) = (8)(2) =16 (4)(2)(2) = (4)(4) =16 - Test Tip: Practice & Memorize! *
Multiplying Long Numbers
Even If You Learn Your Multiplication Tables Up To 12, You Will Sometimes Have To Multiply Bigger Numbers With More Than One Digit.
Example: You Would Multiply 365 Days X 24 Hours To Find Out How Many Hours Are In A Year. For Larger Numbers Use A Calculator!
Using Multiplication To Calculate Area
One important Way You Will Use Multiplication In Your Test Is To MEASURE THE AREA OF SHAPES! The Area Is The Amount Of Space Or Surface In A Shape. Let’s Practice!
Multiplication By Measuring The Area Of A Surface
You Can Use Lots Of Different Units To Measure The Length Or Something Inches, Cenimeters, Miles, Kilometers, To Measure Area, You Have To Find A Way To Express The Width Of Something As Well As Length. You Can Do This With Units Of Measurements Called Square Units.
Square Units Are Square Inches, Square Cenimeters, Square Miles, Etc. You Can Picture A Square Mile, Or A Square Inch, Because You Know What Miles And Inches Are. Think Of A Square Field. 1 Mile Long & 1 Mile Wide, Its Area Is 1 Square Unit.
In Math, We Can Use The Idea Of Square Miles And Any Other Square Units To Measure All Sizes Of Area. Now Think Of Another Field, A Rectangle 2 Miles Wide And 3 Miles Long. How Big Is That Area? To Find Out, Just Multiply Its Width By Its Length. 2 x 3 = 6, So The Field Is 6 Square Miles. That Gives You A Good Idea Of How Big An Area It Is!
So The Rule, Or Formula, For Finding The Area Of A Square Or Rectangle Is: Area = Length x Width. You Can Write It Like This: a = L x W
Now That You Can Multiply, You Can Use This Formula To Find Areas.
Example: What Is The Area Of A Piece Of Paper That Is 5 Inches By 8 Inches?
A Piece Of Paper Is The Shape Of A Rectangle. The Area Of A Rectangle (a) Equals LxW. So, a = 5 x 8, Which Is 40. The Piece Of Papers Area Is 40 Square Inches.
Once You Know Which Numbers To Multiply, You Will Be Able To Answer Many Of The Questions On Your Test.
26 x 2 43 x 2 37 x 2
52 + 86 + 74
212
- Study Quiz: 100% 6 out of 6 correct *
