Multiplication

Multiplication

2x1 and zeros trick

What is multiplication?

• Multiplication is repeated addition

• What this means is that multiplication is a faster way to add

• If we have 7 bags of flowers, and there are 34 flowers in each bag, its easier to multiply than to add 34, 7 times.

• Especially since we are getting into bigger numbers this year

2x1

• Start with the ones place. The bottom number will multiply the top number. Just like in the picture

• Next you will multiply the bottom three with the top three

• This is what you learned in 3rd grade

• let's practice this

Multiple Choice

83x 2=

• 85

• 106

• 116

• 166

Multiple Choice

16x6

• 360

• 96

• 160

• 66

Multiple Choice

33x8

• 480

• 280

• 264

• 126

Multiplying by 10's, 100's and 1,000's

• When we multiply by 10's, 100's and 1,000's all we are doing is adding zeros to the end of the numbers. Look at the pattern

• 2x10=20

• 2x100=200

• 2x1000=2,000

• Notice how we added zeros to the end of the answer

Multiplying by 10's, 100's and 1,000's cont.

• Any time we have zero's in our bottom number, we can just add the zeros

• For example 7x200

• 7x2=14

• Add two zeros to the end because that's how many zeros are in 100

• So our answer is 1,400

• try one on your own: 5X5,000

• what about 23x100?

Multiple Choice

80x10

• 8000

• 8

• 80

• 800

Multiple Choice

4,696x100

• 4,696

• 4,960,900

• 469,600

• 446,600

Multiple Choice

36x10

• 300

• 360

• 400

• 460