Sunday, October 14, 2012

Singapore Math Method for Compensation Subtraction

After years of doing intervention work with subtraction across a zero, I was so excited when I learned about compensation subtraction.  It's also called constant difference.  It helped so many kids and it wasn't just a trick.  They understood why they were doing it!
When I taught larger numbers, I generally reverted to the traditional method, or used many steps.  After spending a really fun week in Cleveland, MS, Lon Hayes sent me an email describing this method of compensation subtraction with larger numbers.  Thanks so much Lon!!
Try this with your class and let me know how it goes!

Wednesday, October 3, 2012

Singapore Math--Extending a Problem

This was a comment on another post...I just wish I had the original problem!

Today I posted some of the part/whole problems around the classroom for student pairs to go around and make models/solve. I had one kid that needed more of a challenge, so I asked him to write more problems... Here are his two problems: Joe bought 26 chairs. They each cost $7.25. How much money did he have to pay? 

 Logan made 64 chairs. He needs 6 wood planks to make 2 chairs. How many planks does he need to make 64 chairs?