Multiplication Tricks: 9 Times

Multiplication Tricks: 9 Times

I will start this blog with a confession. I loved math in school. I competed in math competitions and took advanced math classes. However, even in my twenties, I was still calculating my 9 times facts on my fingers. No matter how hard I tried I could never memorize them in school.

As my kids started to learn math they had similar troubles. They loved the thinking parts of math but struggled with the memorization. Just as I did they needed to learn math “tricks” instead of memorizing math facts. Then, after relying on the trick for a while, they would eventually memorize the fact.

9 Times with Your Fingers

My favorite math trick is calculating 9 times using my hands. Here’s how to do it with 9 x 6:

  1. Hold up all 10 fingers in front of you.
  2. Going from left to right find your 6th finger and lower it.
  3. Count the number of fingers to the left of the 6th: 5
  4. Count the number of fingers to the right of the 6th: 4
  5. 9 x 6 = 54

The trick works with any number from 1 to 9. Try it yourself. It takes one of the hardest multiplication facts and makes it one of the easiest.

9 Times with Subtraction

For those who don’t want to use their hands you can also calculate 9 times using only subtraction. First let’s take a look at all the multiples of 9:

9, 18, 27, 36, 45, 54, 63, 72, 81, 90

Each of the above numbers has an interesting trick. If you add all the individuals together they will always equal 9.

  • 1 + 8 = 9
  • 2 + 7 = 9
  • 3 + 6 = 9
  • 4 + 5 = 9
  • 5 + 4 = 9
  • 6 + 3 = 9
  • 7 + 2 = 9
  • 8 + 1 = 9
  • 9 + 0 = 9

To use this to calculate 9 x 6 do the following:

  1. Subtract 1 from the number: 6 – 1 = 5
  2. Figure out what number adds to that number to get 9: 5 + 4 = 9
  3. Put the two numbers together and get the answer: 54

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