Math Mammoth in Cathy Duffy's 101 Top Picks!

100 Top Picks for Homeschool CurriculumYou might have heard of this popular homeschool book, 100 Top Picks for Homeschool Curriculum by Cathy Duffy. Math Mammoth has been included as one of the top picks for the newest edition of this book, just coming out!

I feel honored about it... years ago, when I started working with the books, I never DREAMED it would come to this!

If you're interested in the new edition of book, Homeschool Buyers Co-op has a group buy for its digital version, ending at the end of this month.

And, if you subscribe to Cathy's newsletter at, you get a $3 discount coupon code for the printed version, I understood.

You can read her review of Math Mammoth in the book, of course, but also on her website as well:

The Fibonacci numbers and converting miles to kilometers

Courtesy of Mararie
This is an INTERESTING application of Fibonacci numbers!

Fibonacci numbers are the sequence
1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, and so on. (Add two numbers in the sequence to get the next one.)

Take two neighboring numbers in the sequence, such as 5 and 8. Turns out, 5 miles is approximately 8 km.  Take 34 and 55:  34 miles is about 55 km.

If your number is not in the sequence, write it as a sum of numbers that are:

Convert 10 miles into kilometers. 10 = 5 + 5, and 5 miles is about 8 km. So, 10 miles is about 16 km.


Convert 25 kilometers into miles. 25 = 21 + 2 + 2.

21 km = 13 miles (about)
2 km = 1 mile (about)
2 km = 1 mile (about)

25 km = about 13 + 1 + 1 miles = about 15 miles.

More details here: Adventures in Fibonacci Numbers

The reason has to do with the fact that the conversion factor, (0.621371192 mi/km) is pretty close to the ratio to which sequential Fibonacci numbers converge (0.61803).

To Listen, To Sense, To See

I'm going to India in a week and a half.


As much as I want to prepare myself in some way, I can't.  I've checked out books about India from the library and returned them unread.  I've briefly reviewed Hinduism, but I took a whole course in college.  And, honestly, I'm not really sure tha I should reschool myself in it for this trip.   My time has actually been spent reacquainting myself with the God that I already know. In some sense I'm setting myself up for an experience that will simply happen to me, like jumping in a lake and emerging drenched in an element that I don't normally exist in.  Floating in it.  Letting it carry me.

I have tried to cram 11 weeks of summer (and maybe a couple years of life) into about 6.  I've gone room by room, closet by closet, putting things in order.  All the appointments that needed to me made (well-child, dentist, travel vaccines, eye exam, the specialist I've been putting off) have been made and just about completed.  Lesson plans have been created up through Thanksgiving.  Family photo albums done to a point.  Women's retreat planned and organized for when I return.  HHacked bank account dealt with.  We've even met with a lawyer to put our living trust, will and powers of attorney together.   I'm definitely getting things done, but I'm not really present in them.

I've spent the whole summer making things happen.  In some ways it has actually been the most intentional time of my life.  Looking deeply at my children when they talk to me. Calling my son when he's home alone.  Taking them places for quality time.  Letting go of other normal summer stuff so I can just be with them playing catch, watching them play, spurring them on, swimming at the pool. When I'm with them, I'm fully present and I know it.

india/varanasi_rolling_beediAm I afraid?  Am I putting my affairs in order as a result of that fear?  Am I drinking in my kids because of it?  Or am I anticipating that life will be different when I return to such an extent that I'm taking note of life as it is now?  Is all my preparation so that I can re-enter with a new set of eyes?  I can begin again with no loose ends to drag me back to what was.  I can simply jump off and move forward. 

Maybe a little of both.

Pray for us as we go and wrestle alongside an indigenous pastor who doesn't quite grasp a God of grace.  We'll pray with those wives who need love for the churches their husbands are leading.  We'll come face-to-face with sex trafficking in action; smell the slum; intervene for the sick.

And we'll also see the restoration that is already being done through charitable works, engineering and church planting... to see what God is doing through his church to end poverty.

Please pray for us to have eyes to see this part of the world as God sees it, to purposefully associate with a culture opposite from our own to make connections and exhibit grace.

And to return made new and fully present.

Math Mammoth Grade 3 now aligned to the Common Core standards

Math Mammoth Grade 3 is now aligned to the Common Core. In this post I try to outline what is same and what is different about this edition compared to the previous one.

cover for Math Mammoth Grade 3-A Complete WorktextWhat is same?

-  The focus on single-digit multiplication and division is the same. I did add more varied word problems to these two sections, and other little 'enhancements' as I edited the lessons, but no major changes here.

- Also, much of the addition,  subtraction, and place value topics are the same. There are some slight differences, yes, but not major ones.

- Time and money sections are the same.

cover for Math Mammoth Grade 3-B Complete WorktextWhat is different?

- The geometry chapter has been pretty much redone. Now, it concentrates on the concepts of area and perimeter (according to Common Core standards). Before, I did have one lesson on area, but also other concepts, such as right angles and parallel lines. Those will be moved to 4th grade.

- In measuring, I have removed most of the content that dealt with conversions between the measuring units, as that is a topic for  4th grade in the standards. I did leave some content and easy exercises about it, though, as I feel 3rd graders are able to do such. I also reorganized some of the material here and added new measuring activities.

- In fractions, I added the topics of fractions on a number line, equivalent fractions, and comparing fractions, and removed the topic of adding and subtracting like fractions.

- The topic of decimal number has been taken off from this grade.