MULTIPLICATIONMs. Behling

3rd grade math

STANDARD USED

Represent and solve problems involving multiplication and division.CCSS.Math.Content.3.OA.A.1Interpret products of whole numbers, e.g., interpret 5 × 7 as the total number of objects in 5 groups of 7 objects each. For example, describe a context in which a total number of objects can be expressed as 5 × 7.

WARM-UP

•What does ‘x’ mean in 2 x 3?

WARM-UP•X=of

•2 groups of 3 = 6 squares

•So, 2 x 3 = 6

PRODUCT

•What does the term product mean?

•When you multiply two numbers together, the answer is the “product” of those two numbers

•What is the product of 2 and 3? 6!

ORDER DOES NOT MATTER

• Commutative property of multiplication: factors can be multiplied in any order and the product is always the same

• For example:

4 x 2 = 8 AND 2 x 4 = 8

• When else can we do this?

Addition!

PATTERNS IN MULTIPLICATION: 0

•When you multiply a number by zero, the product will always be zero

• 0 x 1 = 0 • 0 x 5 = 0 • 0 x 8 = 0

PATTERNS IN MULTIPLICATION: 1

When you multiply any number by 1, the product of the two numbers is itself

• 1 x 1 = 1

• 2 x 1 = 2

• 3 x 1 = 3

• 10 x 1 = 10

• 564 x 1 = 564

• Is this always going to be true?

PATTERNS IN MULTIPLICATION: 2

•When you multiply a number by 2, the number doubles, as if you were adding it to itself.

• For example: 7 x 2 = 14 JUST LIKE 7 + 7 = 14

PATTERNS IN MULTIPLICATION: 5

• When you multiply a number by 5, the product will either end in a 5 or a 0.

5 x 1 = 55 x 2 = 105 x 3 = 155 x 4 = 205 x 5 = 25

5 x 6 = 305 x 7 = 355 x 8 = 40 5 x 9 = 455 x 10 = 50

PATTERNS IN MULTIPLICATION: 9

• When multiplying a number by 9, hold up all 10 of your fingers with your palms facing away from you

• if you’re multiplying 2 x 9 then put down your second finger

• The fingers that are left on each side of the finger that is down gives you your answer

• For example with 2 x 9 when your second finger goes down, there is one finger left up to the left and 8 fingers left up to the right because 9 x 2 = 18

PATTERNS IN MULTIPLICATION: 10

• When you multiply a number by 10, the product will be that number with a zero added to it

10 x 1 = 1010 x 2 = 2010 x 3 = 3010 x 4 = 4010 x 5 = 50

10 x 6 = 6010 x 7 = 7010 x 8 = 8010 x 9 = 9010 x 10 = 100

PRACTICE

•Work on worksheet of practice problems with a partner

•When I ring the bell switch partners and keep working

•When I ring the bell a second time, go back to your seats and sit quietly

HOMEWORK

•Write out 15 multiplication problems for a classmate to solve tomorrow

•On another page write out an answer key for your own problems for you to turn in