Mastering Whole Number Operations

 Addition and Multiplication involves all single digit addends and factors  Addend plus addend equals sum  Factor times factor equals product  How many basic facts are there????

 100!!!! For each addition and multiplication  How???

1. Understand the meaning of the operations 2. Use thinking Strategies to Retrieve Facts *use facts that they know to figure out facts that they don’t i.e. 2+2 =4 so 2+3 must be one more than that * other stategies include counting on, counting back, skip counting, one more, one less…

3. Using Consolidating Activities for Drill and Practice games, activities, worksheets all help children memorize these facts

 Counting on … 6+3 start from the 6 and count on three times seven, eight, nine  Remind children to start from the larger # regardless of order of the problem..3+6 still starting at 6 and add on three more  This method works well for both addition and subtraction  Sometimes a calendar works as a good visual to use this method—see next slide

January 2012 SundayMondayTuesdayWednesdayThursdayFridaySaturday 1 New Year’s Day Martin Luther King Day

 Use counters 1. Show two groups of 6 2. “How much is 6+6?” 3. Add one more to one of the groups 4. Now we have “How many altogether?” 5. One more than twelve 6. Count out 13 objects with students = 12 then = 13

 One addend is increased while the other addend is decreased by trying to make one addend 10  Use counters to model two piles 8 + 4=?  Manipulate counters so one pile has 10  Now solve

 Order doesn’t matter  3+5 = = 53 However this does not work for Subtraction and Division 6-4 ≠ /6 ≠6/24

 4  7  17  37  33  13  53  59  89

 John’s calculator is broken. The number 4 key will not work. How may possible combinations can you come up with on the screen to get 4 without actually using 4?  John has a math problem for hw and he is still trying to use the same calculator to solve this problem 24-4= ? Can you help him rewrite this problem so he can use his calculator?