## Posts

Showing posts from October, 2007

### Carnival time

Carnival of Homeschooling is hosted at Sprittibee's. this one is the "yearbook edition"... beautifully done.

### Speed versus accuracy in math

Just go read this very interesting story at Ragamuffin Studies blog: Taming the speed demon.

### Up for some challenge in math? Try contests!

Could a nice math contest spark up some interest and motivation in your student(s)?

I really like the idea of math contests and problems of the week. When my kids get a little older, I'll probably use some problem of the week contest from the Internet.

Typically with problem of the week contests you simply do the problems at home and send the solution over the Internet. You, as the teacher, can be in control of time and additional resources used.

The contest problems are more challenging than standard textbook problems. They "stretch their brain", perhaps even strech mom's brain! But that's all for good. We must not let our students live under the impression that all word problems are solved by the method just studied in the lesson.

I've written about the need for challenging and open-ended problems before. You might want to check those posts out as well.

Some contests publish the names of those who solved it right and some simply publish the right solution. Eit…

### Multiplying in parts and the standard algorithm

I haven't blogged for a while but I've been thinking about this topic for a little while now. It is your multiplication algorithm, also called long multiplication, or multiplying in columns. I also happen to be writing a lesson about it for my upcoming LightBlue series 4th grade book.

The standard multiplication algorithm is not awfully difficult to learn. Yet, some books advocate using so-called lattice multiplication instead. I assume it is because the standard method is perceived as being more difficult. But let's look at it in detail.

Before teaching the standard algorithm, consider explaining to the students multiplying in parts, a.k.a. partial products algorithm in detail:

To multiply 7 × 84, break 84 into 80 and 4 (its tens and ones). Then multiply those parts separately, and lastly add.

So we calculate the partial products first: 7 × 80 = 560 and 7 × 4 = 28. Then we add them: 560 + 28 = 588.

If you practice that for one whole lesson before embarking on the actual algori…

### Denise's fraction quiz

I want to point out to you a post by Denise at Let's Play Math. She has a quiz concerning fraction rules: can you explain to your children why this way or why that way, as concerning fractions?

Quiz: Those frustrating fractions

QUOTE:
Question #1

If you need a common denominator to add or subtract fractions, why don’t you need a common denominator when you multiply?
Maybe you can explain why, maybe you can't. But don't worry. She's going to continue the topic and explain all of these, on her blog. Don't miss that.

### From the mouth of a child

Background: my daughter has been learning about 3-digit numbers and she's pretty confident with numbers that have hundreds now. She's also heard us adults mention some bigger numbers.

Today she said that she knows how the numbers go:
"Hundred, thousand, million, googol, and gamazon."

What's a "gamazon"??

It's a new number she made up, which "comes after googol and nine hundred ninety-nine."

I guess she's learned something anyway.

### Archimedes knew more than we thought

This story is fascinating; they found a long-lost works of Archimedes under the text of a prayer book, and used modern technology to "see" under the prayer text.

After the text was recovered, it was discovered that Archimedes actually found some of the principles of calculus, and used them to figure out volumes and areas. He dealt with "actual" and "potential" infinity, which is exactly what calculus is about.

And he lived thousands of years before Newton!

A long-lost text by the ancient Greek mathematician shows that he had begun to discover the principles of calculus.

### Word problems in Singapore math and bar diagrams

If you're interested in Singapore math's word problems, and how their bar diagrams work, check out this blog entry by Denise at Let's Play Math:

She goes through a bunch of word problems from Singapore Math 3-A book, and explains both a solution based on algebraic thinking, and a solution with bar diagrams.

It's good reading for all of us who teach, actually.

### Math card game for all four operations (elementary)

I'm sure youngsters will like this card "game"! I'm going to try it with mine.

Actually it's not really a game, but a fun way for kids to write some of their own math problems using a deck of cards. She even provides a free printout:

Little Blue School: Math Card Game for Addition, Subtraction, Multiplication, Division

HT: This week's Carnival of Homeschooling

### Factoring worksheets

I took time yesterday to make a new worksheet generator. I always enjoy building those; I like simple programming like that and the math in it.

But while doing it, I almost felt I should have been answering emails or doing some of the other projects I have...

Anyway, here it is:

Generate free factoring worksheets - factorize numbers to their primer factors.

### Math Mammoth and other curricula

I wrote some thoughts concerning the comparison between Math Mammoth Lightblue series and other homeschool math curricula.

It's not complete, and I'd appreciate your thoughts, as well, to add to the page.