Over the past few weeks I have worked with small groups to help us learn addition strategies. We focus on... Plus 1 and Pl;us 2 Counting on Doubles Doubles Plus 1 and Doubles Plus 2 Make a 10. I want to explain some of the strategies. This way when you're helping with homework you are familiar with the language we use in class as well as strategies to help your child. Plus 1 and Plus 2The picture above demonstrates one more or two more than a number. Students should start with the bigger number and understand one more and two more. Students would start with the 5. They would say "1 more than 5 is 6." Students would start with the 6. They would say, "2 more than 6 is 8." Count OnCounting on means the student does not need to count 6 and then count 4 more. The student should know 6 automatically (because they see the number) and then count on from there. Students would say, "6...7, 8, 9, 10" DoublesOnce students know facts within 10, we start learning doubles. Students should know doubles starting with 1+1 and ending with 10+10. They should know these from memory with no counting. Students would say, "I know 5 and 5 is 10." Doubles Plus 1Because students understand 1 more, and they also know doubles facts, this strategy combines those two ideas to create more efficient problem solving. Students would look at 5+6 and realize 6 is close to 5. They could break 6 down to be 5+1. So the problem would look like 5+5+1 in their head. Students would then put together 5+5 to make 10 and then say "1 more than 10 is 11." Doubles Plus 2This is an extension on Doubles Plus 1. Students can see the "near doubles" fact and manipulate the numbers to break it into smaller, easier to manage, numbers. Students would say, "If I take away 2 from 8 I have a doubles problem. 6+6 is 12. I add the 2 back on. 2 more than 12 is 14." This can also be viewed as a Doubles Minus 2 problem, using 8+8 instead of 6+6. Make a 10Make a 10 is our most difficult strategy. If students can manipulate Doubles plus 1 and 2 they can easily transition to Make a 10. The idea is to see 10 in the numbers and add on from there (since 10 is really easy to add on to). Students would say, "If I take 1 away from 7 I have 6. I put the 1 with the 9 to make 10. So 9+7 = 10+6 = 16." This can be applied to other decade numbers once understood (20, 30, 40...).
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April 2014
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