Did you know that if you can count forwards from 1 to 10 and also backwards from 9 to 0 you already have all you need to create the 9's times table from 9 X 1 all the way to 9 X 10? All you have to do is a little arranging. First let's start by listing the numbers 1 through 10 in a column.
1
2
3
4
5
6
7
8
9
10
That was easy enough, now lets add "X 9 = " to the right of each number in the column.
1 X 9 =
2 X 9 =
3 X 9 =
4 X 9 =
5 X 9 =
6 X 9 =
7 X 9 =
8 X 9 =
9 X 9 =
10 X 9 =
Great, so far so good! Now comes the counting. First lets count from 0 to 9 and list the numbers from top to bottom.
1 X 9 = 0
2 X 9 = 1
3 X 9 = 2
4 X 9 = 3
5 X 9 = 4
6 X 9 = 5
7 X 9 = 6
8 X 9 = 7
9 X 9 = 8
10 X 9 = 9
Wonderful! We are not quite there yet, but one more pass and we will have the solution! This time we are going to count backwards from 9 to 0 starting at the top. Don't worry, if you haven't quite mastered how to count backwards, you can count always count forwards from 0 to 9 starting at the bottom :) Ready? Let's do it!
1 X 9 = 0 9
2 X 9 = 1 8
3 X 9 = 2 7
4 X 9 = 3 6
5 X 9 = 4 5
6 X 9 = 5 4
7 X 9 = 6 3
8 X 9 = 7 2
9 X 9 = 8 1
10 X 9 = 9 0
Now, observing that 09 is no different than 9 we can change the top equation to 1 X 9 = 9 and we have arrived at our solution!
1 X 9 = 9
2 X 9 = 18
3 X 9 = 27
4 X 9 = 36
5 X 9 = 45
6 X 9 = 54
7 X 9 = 63
8 X 9 = 72
9 X 9 = 81
10 X 9 = 90
Quick, Easy, Simple, Satisfying! :)
If you like what you have seen here, please feel free to share this post with all your friends and math enthusiasts, and make sure to come back for more helpful math, science, and computer programming tricks! Also check out my YouTube channels Paul Programming and Learn Math Tutorials for additional great content! I look forward to seeing you soon, and remember to have fun out there!
-Paul (aka VeryScience)
In closing, I'll leave you with the following quote,:
"The Most Exciting Phrase in Science Is Not ‘Eureka!’ But ‘That’s funny …’ "--Isaac Asimov
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The (two) digits also add up to nine. This could be used as a check.