This podcast video is from my Free Math Worksheets series, which you can access here.

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Free Math Worksheets: 9 Times Tables

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## Teaching the 9x Nine Times Tables

Multiplying by 9 raises some really simple and interesting patterns, which you can use to help children to learn this set of number facts or times tables.

As explained in the video, if you start with the equivalent multiple of 10, you can then compensate to quickly find the 9x answer. For example, think about 8x9:

• 8 x 9 = ?
• 8 x 10 = 80
• Subtract 8 ones (one for each set of 10): 80 - 8 = 72
• 8 x 9 = 72

### 9x Tables: Sum of Digits Equals 9

Look at the multiples of 9 up to 90, and check out the sum of the tens digit and the ones digit in each multiple:

• 09  :  0 + 9 = 9
• 18  :  1 + 8 = 9
• 27  :  2 + 7 = 9
• 36  :  3 + 6 = 9
• 45  :  4 + 5 = 9
• 54  :  5 + 4 = 9
• 63  :  6 + 3 = 9
• 72  :  7 + 2 = 9
• 81  :  8 + 1 = 9
• 90  :  9 + 0 = 9

Students can use a two-step process which takes advantage of the above pattern:

• 6 x 9 = ?
• There must be 5 tens (because we know it is a bit less than 60)
• So, 6 x 9 = 5?
• If the digits in the answer add up to 9, what is the other digit; ie, 5 + ? = 9. The other digit must be '4'
• 6 x 9 = 54

### 9x Tables: Finger Trick

Put both hands up in front of you, palms facing away. Imagine that each finger is numbered, from left to right, from 1 to 10.

To find a multiple of 9:

• 3 x 9 = ?
• Hold up your hands, thumbs together
• Put down the finger that corresponds to the number multiplying the 9: the third finger
• Count the fingers to the left of the finger that is down: 2 - this is the number of tens
• Count the fingers to the right of the finger that is down: 7 - this is the number of ones
• 3 x 9 = 27

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