Post on 27-Mar-2015
9 As A Factor9 As A Factor
By Karen MastinBy Karen Mastin
Challenger ElementaryChallenger Elementary
Using Patterns to Find the ProductsUsing Patterns to Find the Products
When multiplying by 9, the tens digits in each product When multiplying by 9, the tens digits in each product counts up by 1 and the ones digits counts back by 1.counts up by 1 and the ones digits counts back by 1.
Scott Foresman----Addison Wesley
ExamplesExamples
TENS ONES
1 X 9 =
2 X 9 =
3 X 9 =
4 X 9 =
Scott Foresman----Addison Wesley
0
1
2
3
9
8
7
6
Use a Strategy to Multiply With 9 Use a Strategy to Multiply With 9 As a FactorAs a Factor
This is the One Less = Nine Method:This is the One Less = Nine Method:
Subtract one from the number you are multiplying by: Subtract one from the number you are multiplying by: 9 x 5, one less than 5 is 4.9 x 5, one less than 5 is 4.
The first number in the answer is 4. The two numbers The first number in the answer is 4. The two numbers that make up the answer will equal nine. 4 + 5 = 9. that make up the answer will equal nine. 4 + 5 = 9. The last number in the answer is 5. 9 x 5 = 45.The last number in the answer is 5. 9 x 5 = 45.
multiplication.com
Use Your FingersUse Your Fingers
multiplication.com
Your fingers represent the numbers 1-10
Insert graphic to demonstrate, from the following website.
multiplication.commultiplication.com
Here is what 9 x 4 looks like. Fold over the finger representing the number you want to multiply nine by. (The finger representing four is curled under.)
Insert graphic to demonstrate from website.
multiplication.commultiplication.com
The first number in the answer the number of fingers before the curled under finger. (3) The second number is the number of fingers after the curled under finger. (6) 9 x 4 = 36
Insert graphic to demonstrate from website.
ConclusionConclusion
Now you are ready to apply these Now you are ready to apply these strategies by completing activities in the strategies by completing activities in the computer lab.computer lab.