Hello,

I was just going over lesson 60 (corners game) in level B. When adding 15, RS says to add the 10 first then the 5, stressing adding left to right. That I understand and we do. I have an older son finishing RS C. But for 25+15, it says to add 10 to get 35 then add the 5. When we've played Corners, my son, when faced w/ a two digit number ending in 5, adds the 5 first to get to the next 10, then add the ten. So 25+15 would be 25+5=30+10. Is it OK for him to use that strategy?

thanks!
Capt_Uhura

Yes! We want your child to know more than one way of getting the answer using mental math. There isn't just one right way to solve problems, but a multiplicity of ways. Therefore we want to encourage our students to see things in as many ways as possible. So give him a pat on the back for his creativity in solving it and enjoy the game together.
Nancy