Rightstart Math Level B...2-Fives Strategy with double digits...

[sherylwinter]

Hi there Rightstart gals/experts :cool::
I am bit confused with this 2-Five High Strategy...maybe someone can help me out. We understand lesson 66 when the book teaches 2-five strategy. Example 7+8=15...5+2 and 5+3 and splitting them up with five and what left and adding those numbers...it took him awhile but he did all the worksheet examples and did them in his head, he got it.
Now the lesson 68 and example on page 137 got me stuck..says take 26+6 ...extra 10 formed by adding 6+6, giving 30+2=32. (This explanation written next to picture of abacus. )Anyways, I didn't get it. The worksheet problems were very difficult for him to do. So I wasn't sure if he was supposed to add them in his head like the other lessons...so example 45+7...I told him to just write down on slip paper, 45+5+2 and add them up in his head after he wrote them down. Next one was 67+7=74...he split up 65,2,5,2 and added up in his head 65+5 is 70 and 2+2 is 4 so 70+4=74
Is this OK or is this wrong. I've tried calling Rightstart for couple days but nobody is answering there.
Thanks for any help.
Sherylwinter (old board called sherylinarctic :)

[prairiegirl]

If he is having problems doing it in his head, let him do it on the abacus. Chances are once he does a few of the problems with the abacus, he will be able to do the rest by entering the numbers on the abacus and doing the rest mentally. Pretty soon, he will be able to visualize the whole concept so that he won't need the abacus at all.

Does that help? Are you a member of the RightStart Yahoo group? If I didn't answer your question properly, you could ask it on the group. There are lots of moms there who would give you a prompt answer.

Julia
mom of 3 (8,7,5)

[Mama Lynx]

For 45 + 7, my son adds the 5 and the 7 first, using the two-fives strategy: 5 and 5 + 2. The two 5s give him a 10, and then he has a 2. He adds these to the 40 from 45: 40 + 10 + 2

For 26 + 6, he would first add the 6s using the two-fives strategy: 5 + 1 and 5+ 1, combine the 5s, and you have a 10 and a 2. Add the 10 to the 20, and then add the 2.

Yes, let him use the abacus, until he gets the trick and can do it in his head. I am doing this lesson with my son right now. We only do 5 of the worksheet problems a day, and review the strategy each day.

[sherylwinter]

Thank you both for replying. I didn't know about the RS Yahoo Group... I will look forward to joining that...will b great to have place to post questions and share with others using same program. And I will get him to use the abacus..we don't use it much unless the example says to use it. Thanks for your help. :)