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multiply by 9 with your fingers

To learn how to multiply a number from your multiplication table by 9 you can use your hands to help you.

Put your 2 hands with your 10 fingers in front of you and give every finger a numbers like this:

Now take the number you want to multiply with and take that finger away.

Count the fingers to the right of this fingers. These are the ones. Then count the fingers to the left. These are the tens. Put them together and you have the result.

1 * 9

If you take the finger with the number 1 away you can count 9 fingers to the right and 0 to the left so the correct answer is 9.

2 * 9

If you take the finger with the number 2 away you can count 8 fingers to the right and 1 to the left so the correct answer is 18.

3 * 9

If you take the finger with the number 3 away you can count 7 fingers to the right and 2 to the left so the correct answer is 27.

4 * 9

If you take the finger with the number 4 away you can count 6 fingers to the right and 3 to the left so the correct answer is 27.

5 * 9

If you take the finger with the number 5 away you can count 5 fingers to the right and 4 to the left so the correct answer is 45.

6 * 9

If you take the finger with the number 6 away you can count 4 fingers to the right and 5 to the left so the correct answer is 54.

7 * 9

If you take the finger with the number 7 away you can count 3 fingers to the right and 6 to the left so the correct answer is 63.

8 * 9

If you take the finger with the number 8 away you can count 2 fingers to the right and 7 to the left so the correct answer is 72.

9 * 9

If you take the finger with the number 9 away you can count 1 finger to the right and 8 to the left so the correct answer is 81.

10 * 9

If you take the finger with the number 10 away you can count 0 fingers to the right and 9 to the left so the correct answer is 90.

Did you notice that to the right you always counted one less and to the left you always counted one more? And if you took the sum of the digits they always added up to 9?