Rule of 9
When multiplying by 9 you can use your fingers or remember that the product is always the number (not 9) subjtracted from the number times ten.
Example: 9 X 8.....8 X 10 = 80 - 8 = 9 X 8 = 72
If the way above doesn't work very well for you, try using the finger method.
Example: 9 X 8.....8 X 10 = 80 - 8 = 9 X 8 = 72
If the way above doesn't work very well for you, try using the finger method.
How did you do? Could you mutiply all the way through?
THE FINGER METHOD
Put your hands in front of you with your plams facing the ground. Your fingers represent the numbers one to ten (one is your left pinkie finger; ten is your right pinkie finger). Now you're ready to do your nine times tables. Let's say the question is 9 x 4. Count to the fourth finger (if you've counted right, it will be the left index (pointer) finger on your left hand and curl that finger under. Now you have three fingers up before that finger and 6 up after it. So the answer is 36. Let's try 9 x 8. Put down the 8th finger (middle finger on the right hand) so that you have seven fingers up before the finger you curled under, and two fingers afterward. So the answer is 72.
Put your hands in front of you with your plams facing the ground. Your fingers represent the numbers one to ten (one is your left pinkie finger; ten is your right pinkie finger). Now you're ready to do your nine times tables. Let's say the question is 9 x 4. Count to the fourth finger (if you've counted right, it will be the left index (pointer) finger on your left hand and curl that finger under. Now you have three fingers up before that finger and 6 up after it. So the answer is 36. Let's try 9 x 8. Put down the 8th finger (middle finger on the right hand) so that you have seven fingers up before the finger you curled under, and two fingers afterward. So the answer is 72.
If you still need more work on your 9s then go to http://www.studyisland.com/ to practice.
