1. DEVELOPING STRATEGIES FOR ADDITION AND SUBTRACTION 2 nd GradeMatt Rinehart

2. Drawbacks to Memorizing Facts  Inefficient – There are too many facts to memorize.  Inappropriate applications – Students don’t check their work and misapply the facts.  Inflexible – Students don’t learn flexible strategies and therefore continue to use counting.

3. REASONING STRATEGIES FOR ADDITION FACTS There are 100 basic addition facts.

4. Adding Zero 3 frogs were in a pond, one hour later no frogs had joined them. How many frogs are in the pond? 3+0=3 Covers 19 facts

5. One More Than and Two More Than There were 7 flowers in the vase on the kitchen table. Mother added 2 more. How many flowers are in the vase? 7+2=9 Covers 36 facts

6. Using 5 as an Anchor 6 is 5+1 7 is 5+2 6+7 is 5+5+ “extras” 1 & 2 There are 6 red lollipops and 7 blue lollipops. How many total lollipops are there?

7. 10 Facts  Use ten-frame cards to help students understand and master the number combinations that make 10.  Helps with basic fact mastery.  Foundation for addition with larger numbers.  Promotes understanding of place value concept.

8. Up Over 10 8+6=? 8 is 2 away from 10 Take 2 from 6 to make 10 Then add remaining 4 to get 14 Extremely important strategy. Heavily used in high performing countries Covers 36 facts

9. Doubles  Easy for students to learn, or already know.  Possibly due to rhythmic nature. Covers 10 facts 2+2 5+5 9+9 4+4 6+6

10. Near Doubles

11. REASONING STRATEGIES FOR SUBTRACTION FACTS There are 100 basic subtraction facts.

12. Subtraction as Think-Addition  Students need to have a strong grasp of additions facts  Students need to understand missing part and part- part-whole concepts student sees 7-3=? student thinks 3 plus what makes 7.

13.  Joe had 3 cookies. His brother gave him some more. Now he has 7 cookies. How many cookies did his brother give him? 7-3=? 3+?=7

14. Down Over 10 or Take From the 10 14-9=? I know 14 is 10+4 I know 10-9=1 1 and 4 is 5 14-9=5

15. CONCLUSIONS

16. What Mr. Rinehart will not do.  use lengthy timed tests.  use public comparison.  require facts to be learned in order.  rush memorization.