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

3. The Nines Pattern Let’s count by nines by adding 9s using add 10 and subtract 1. Click your mouse to see the pattern develop. + (10 – 1) = 18 Two Nines + (10 – 1) = 45 Five Nines + (10 – 1) = 54 Six Nines + (10 – 1) = 63 Seven Nines + (10 – 1) = 72 Eight Nines + (10 – 1) = 81 Nine Nines + (10 – 1) = 27 Three Nines + (10 – 1) = 36 Four Nines 9 One Nine MathOnMonday© (March 2000)

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

5. 9 x 4 = 9 x 2 = 9 x 3 = 9 x 5 = 9 x 6 = 9 x 7 = 9 x 9 = 9 x 8 = 3 1 2 8 4 5 6 1 7 8 5 6 7 2 4 3 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. MathOnMonday© (March 2000)

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