MathOnMonday® Presents: Building Math Courage® A program designed for Adults or Kids who have struggled to learn their Math in the traditional classroom! Lesson 20.9 Learning Your Nines Dirk M. Horton dirk@mathonmonday.com

10’s Digit of Product 1’s Digit of Product Multiply by Click your mouse to find the relationship between the “multiply by” and the “10’s digit” of the product. -1 9 x 4 = 9 x 2 = 9 x 3 = 9 x 5 = 9 x 6 = 9 x 7 = 9 x 9 = 9 x 8 = 1 8 1 + 8 = 9 2 + 7 = 9 3 + 6 = 9 4 + 5 = 9 5 + 4 = 9 6 + 3 = 9 7 + 2 = 9 8 + 1 = 9 2 7 The 10’s digit of the product Is 1 less than the “multiply by”. 3 6 4 5 Click your mouse to find the relationship between the “10’s Digit” and the “1’s digit of the product. 5 4 6 3 7 2 The 1’s Digit + the 10’s digit of the product always = 9. 8 1 -1 MathOnMonday© (March 2000)

Click your mouse to see that you learned your 9s Click your mouse to see that you learned your 9s. Click for the problem, think about the 10’s digit, click again, and think about the 1’s digit, click again and see the result. 9 x 3 = 2 7 9 x 9 = 8 1 9 x 5 = 4 5 9 x 4 = 3 6 9 x 2 = 1 8 9 x 6 = 5 4 9 x 8 = 7 2 9 x 7 = 6 3 MathOnMonday© (March 2000)

One More Time! Click your mouse to see that you learned your 9s. Click for the problem, think about the 10’s digit, click again, and think about the 1’s digit, click again and see the result. 9 x 3 = 2 7 9 x 9 = 8 1 9 x 5 = 4 5 9 x 4 = 3 6 9 x 2 = 1 8 9 x 6 = 5 4 9 x 8 = 7 2 9 x 7 = 6 3 MathOnMonday© (March 2000)

Well done you are learning your nines Well done you are learning your nines! Practice a few times and you be a nines expert! 9 x 3 = 2 7 9 x 9 = 8 1 9 x 5 = 4 5 9 x 4 = 3 6 9 x 2 = 1 8 9 x 6 = 5 4 9 x 8 = 7 2 9 x 7 = 6 3 MathOnMonday© (March 2000)