A Negative Number Black Hole Consuming the Universe (Especially M&Ms)

I suppose as a kid, it’s tough to focus on learning something new when your dad tells you that the entire universe might be erased by a minus sign.

We’d pretty much exhausted the positive integer subtraction worksheets, but had a high-motivation goal on the table involving another iPod download here, so something had to fill the gap in the space-time continuum… I figured it wouldn’t be a big deal to toss out one of the introductory subtraction pages on negative numbers because I had the time to introduce the concept and work through a few examples.

Unfortunately, as far as my young charge was concerned, negative numbers might as well have come from Mars. Or worse. Much, much worse.

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The site has been live now for just over two months and just crossed the 2,000 worksheet mark. Given the number of infrastructure advancements, that’s a huge milestone. The quality control group here is requesting some let up, but I do hope the progress will continue and that you’ll find plenty of useful content. I’ll try to find more incentives to keep the QA team happy.

Meanwhile, I hope you’ll check out the new content. A new set of worksheets for Long Division with Detailed Answers has been added. Additionally, all of the division worksheets have been revised to use the box layout more commonly used to show these problems. This layout looks more similar to the RocketMath sheets used by many schools, and also allowed the long division worksheets to show each step used to come up with the answers.

A very complete collection of number ordering worksheets has been added to the site. The worksheets are broken down into separate sets for whole numbers, decimal numbers, negative numbers, plus various combinations. These worksheets should make a great resource for reinforcing the understanding of place value, and you should find specific configurations for any individual concepts that aren’t being readily grasped.

This is definitely one of the more comprehensive topic coverages on the site, but if I missed a combination, post a comment and let me know!

Oooh boy. It’s been a wild week in the stock market. With the Dow Jones Industrial Average (the DJIA or the “Dow”) swinging madly up and down several hundred points at a day, 100 year old companies biting the dust and comparisons to 1929 in the wind, a number of family and friends around here grew a healthy crop of gray hair. So while everyone had the daily change in the Dow right on the tip of their tongue, it turns out almost nobody could actually describe what a change in that number really means.

People associate up moves on the Dow with healthy markets, a strong economy, sunny days, bumper farm crops, and who knows what else. Investors assume the Dow is a reliable market indicator, but in reality, the Dow is poorly constructed, tells little and should never be used as a benchmark. I haven’t used the Dow in decades […]. My advice to you is you will see markets better if you train yourself to ignore the Dow for the rest of your life as well.

- Ken Fisher, #271 on the Forbes 400, from his book The Only Three Questions That Count

As you might guess from Ken’s opinion, the Dow itself isn’t exactly a straightforward number, and even the components from which the big number is derived don’t match measure value the way people generally expect. To find out what a change in the Dow means in real dollar terms, you need to understand how it is calculated… And that will lead you directly to Ken Fisher’s conclusion that the Dow is pretty much useless.

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If only there were actually a math fire department to come rescue me here. The rounding homework assignments started coming home this week and it was clear the house was in flames from the first one.

It’s not like we haven’t covered this, and I know we hit at least a dozen rounding pages in the Doring Kindersley books, so I was flabbergasted. I mean honestly, we’ve been working on multiple-digit multiplication and reducing fractions lately… You would forgive me for thinking we were past this. Apparently not.

What to do? Rounding worksheets. Lots of them. Right here.