## Visualizing Large Numbers with Pennies

It’s an oldie, but a goodie and one we’ve used a few times here before…

The MegaPennyProject

When we start discussing topics with very large numbers, for instance the finance worksheets from earlier this week, or atomic dimensions in chemistry, it’s helpful for kids to relate it to something familiar and physical. In a more adult context, I heard someone asked in an interview to estimate the number of pennies it would take to span the Golden Gate Bridge, which in case you were wondering…

 4,200 feet 1
×
 12 inches 1 foot
×
 1 penny 0.75 inches
= 67,200 pennies

Imagining physical sizes of things is a great tool, even for adults. And if you can take those thought experiments beyond the usual “how many jellybeans in the jar” questions that can be demonstrated in real life, into the realms of “how big would a million pennies be?” it helps make these millions, billions and zillions all a bit more meaningful. The illustrations at the MegaPenny project are a fun place to start.

## Investing Basics and Market Capitalization Worksheets

Math plays a heavy role in finance and investing, perhaps even a bigger role than in the core sciences. A key goal in raising our girls is to make sure they grow up not just math literate, but financially literate as well.

Stocks, bonds, mutual funds and their derivatives are all plenty confusing when you get started. We’ve been investing for college for some time, and I’ve used that as an opportunity to explain the abstract ideas of “owning part of a company” as being equivalent to stock or “buying part of a loan” as a bond. Getting right down to the price of these market beasties is a whole other game, though.

Read the rest of this entry »

## Analog Elapsed Time Worksheets Updated

Reader Ann McCarty pointed out some duplicate problems showing up on the Analog Elapsed Time worksheets, specifically the sets that all start from noon and add either whole hours or hours and minutes.

All of the elapsed time worksheets should now show much more variability in problems selected on each sheet.

Analog Elapsed Time Worksheets

## Math Riff: The Cruel Math of Weight Loss Multiplication

Raise your hand if one or more of your new year’s resolutions are “get in shape” or “lose weight” or “By Halloween, look just like Gerard Butler for that Spartan warrior costume I’ve twice now skipped in favor of the Energizer Bunny suit.” What? No?

The sad news from the scale this morning is that I’m 16 pounds away from my resolution goal weight, and while I’m making progress already, it’s slow. I saw a Science Channel program where a guy lost something like 12 pounds in one day. By swimming the English Channel. Still, I can do this.

To get motivated, I decided to do a little math. Mayo Clinic says there are 3500 calories in a pound of body fat, and the elliptical machine is reporting that I’m burning calories at a rate of 800 per hour, so a little unit conversion math would surely tell me I could work this weight off with a couple of days of serious commitment…

 16 pounds 1
×
 3,500 calories 1 pound
×
 1 hour 800 calories
=  70 hours

Ouch. These are not the results you were looking for, Obiwan. In fact, my left calf just developed a cramp I think to make darn sure my brain was on the same page with the the muscular/skeletal system’s assessment of these figures.

And, you know, thinking more about it, that Energizer Bunny suit was awfully slimming.

## Division with Remainders and Exponent Flash Cards

Adding on to last week’s printable flash cards, you can find links below to additional division flashcards featuring 10, 11 and 12 as divisors, and also flash cards with easy remainders similar to the Division with Remainders worksheets…

Division Flash Cards Divisors 10, 11, 12

Division with Remainders Flash Cards

Additionally, the previous division flash cards have been updated so that the answer hint at the top of each card (the side you’re looking at while you show it to your student) is no longer in the division box format and now (cough) actually shows the quotient.

Also, a quick set of flash cards for common exponents can be found at this link…

Flash Cards for Common Exponents

Have a great week!