Spreadsheets: Excel: conditional formatting

The tutor opens the discussion about how to display, automatically, a cell’s content according to its value.

What if, in Excel, you want to display any value between 78 and 93 in green? Well, you can, using conditional formatting. On the Home screen, The icon appears in the Styles group, perhaps to the right of center.

For our example, you’d click Conditional Formatting, then New Rule…, then
Format only cells that contain; a dialogue box will appear. In it, you’ll see a choice box where between can be selected; just to the right you can enter the lower and upper limits (in our case, 78 and 93). You’ll see a Format… button which you can click to set specific text attributes. The Color drop-down menu may say Automatic; you’ll have to click the arrow to see the color choices, then click the one you want. Afterwards, you’ll have to click the OK button in both pop-ups to apply the conditional format.

In my experience, Excel’s between is inclusive; therefore, if you signify that numbers between 78 and 93 should be green, 78 will be.



Microsoft Office support

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Music: decrescendo vs diminuendo

The tutor clears up an issue he’s wondered about for years.

As a kid I was trained in music. Two of the first terms we learned were crescendo and diminuendo. Crescendo meant getting gradually louder, while diminuendo meant the opposite: the the gradual change from loud to quiet. Others I’ve talked to agree they were taught the same.

Since about ten years back, I don’t hear people say diminuendo; instead, they say decrescendo. While the term makes sense, why has it replaced diminuendo? With the curiosity of an academic, I resolved to find out.

According to the website the-difference-between.com, diminuendo actually means the mark that indicates gradual change from loud to quiet, or else it can point to a passage of music over which the volume adjusts gradually from loud to quiet. The actual trend of going from loud to quiet is decrescendo.

The distinction between diminuendo and decrescendo is subtle enough that I can understand why, as kids, some might only have been taught diminuendo.


Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Lifestyle: mobile phones: how to create a newline when texting (Android, Nexus 4)

The tutor delivers the goods about how to create vertical space in a text.

I don’t text very often, but much more than before. I’m learning how to do it better.

Whatever message I’m sending, be it a solution on the white board or just a simple text, I like lots of white space: it can be an important organizational tool in messages.

Trying to send a text today, I wanted a blank line between two sentences, but couldn’t see how to do so. The native keyboard on my Nexus 4 doesn’t present a carriage return – at first. Yet, I knew it could be done easily, somehow.

I checked several websites where the question was asked, but not satisfactorily answered for my case. Then, at forums.lenovo.com, I did find the answer – although not until page 2.

On a keyboard like mine, if you hold down the Caps arrow, the smiley face at bottom right converts to a carriage return. On mine, to get the carriage return to stay there long enough to press it, the Caps arrow needs to be tapped twice (it seems, anyway).

Happy texting!

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Lifestyle: bird identification from field guide: white-crowned sparrow

The tutor shares another backyard identification.

If a person isn’t looking closely, a white-crowned sparrow is easy to miss, even in the yard. They forage on the ground, but can seem from a distance to be dull-colored and “just another bird”.

In fact, the white-crowned sparrow has a distinct song, but I don’t notice that it sings when it’s on the ground. You hear this arresting call, but can’t necessarily tell whence it came.

With the binoculars I identified a white-crowned sparrow last week. Only through them could I see the four distinct black stripes along its face and head, separated by glossy white. The white crown is unmistakable. The body is olive or brown, with black spots on the wings.

White-crowned sparrows are very common on the west coast; I’ve just never noticed one before. I’ll be sharing more of my backyard discoveries in future posts:)


Robbins, Chandler S., et al. Birds of North America: A Field Guide to Identification.
  New York: Golden Press, 1966.

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Lifestyle: plant identification from field guide: ribwort

The tutor shares another patient discovery.

Walking home from dropping the car at my wife’s work, I’ve noticed a plant growing along the path in the field. It has long thin leaves around the bottom, then a long thin stem rises to a single flower. The flower is distinct in that it has a conical center surrounded by long, protruding stamens. The anthers appear to form a galaxy around the pistil.

The plant is ribwort; I didn’t find it easily in the guide, since it’s in the “other families” section. It’s common around here, but from Eurasia.

I’ll be sharing more of my finds:)


Pojar, Jim and Andy MacKinnon. Plants of Coastal British Columbia. Vancouver:
  BC Ministry of Forests and Lone Pine Publishing, 1994.

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Home computer use: why 16GB might become 14.8GB from the computer’s point of view

The tutor attempts to explain a possible misunderstanding.

A few days ago I posted about buying my kids each a 16GB flash drive by PNY. Today I showed my younger kid how to access it on Windows (he’s used to Mac from school).

“Why does it say 14.8GB, when it’s 16GB?” he asked.

Of course, it’s an obvious question. I’d say there are two reasons for the apparent discrepancy. The lion’s share of the difference can be accounted for by the fact that, in computer science, 1kilobyte, or 1kB, is not actually 1000 bytes; rather, it’s 2^10=1024 bytes. In that same context, 1GB=(1kB)^3=(1024)(1024)(1024)=1 073 741 824 bytes. It’s about 7 percent more than the flat 1 000 000 000 bytes that the prefix “giga” would normally suggest. (Comp-sci people have their own definitons for the prefixes such as kilo and giga.)

Therefore, from a comp-sci point of view, 14.8GB=14.8(10737741824)=15 891 378 995 bytes. That’s 15.89GB, from the standard definition of “giga”. So, 14.8GB (comp sci) = 15.89GB (normal “giga”).

The other “missing” 0.11GB, I suspect, is used in formatting. When storage space is prepared to receive data, it’s organized internally. That organization – called formatting – takes up some memory.

So, if the 16.0GB statement on the box means 16 000 000 000 bytes, the claim seems correct. It’s just that, in comp sci, “gigabyte” means 1 0737 741 824 rather than 1 000 000 000 bytes. That’s how, internally, 14.8GB resolves to the 16.0GB printed on the box.


Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Lifestyle: plant identification: red dead-nettle

The tutor shares an identification that needed patience.

Early this spring, I began noticing a plant that stood apart. Like so many other wild plants, it grows on vacant properties and path edges. However, this plant has some peculiarities:

  1. It flowers early in spring.
  2. It has small, pink, tube-shaped flowers with a distinct lower lip.
  3. Its leaves are opposite, gradually shrinking up the plant so they form a neat cone.
  4. Its leaves are reddish, especially near the top.
  5. It propagates easily, obviously able to cover large areas.
  6. It seems to like gravel flats, where few other plants have an easy time.

Seeing the plant, I knew I hadn’t come across its picture in my field guide. Yet, I trust the local plants to be in there. I’d re-examine the plant when I passed, hoping to find a new characteristic to help me identify it. Then, I’d search the guide again without success. The pattern continued for weeks.

Keying descriptions of the plant into the web browser didn’t help, either, until one query yielded the response “nettle”. I realized the mystery plant could resemble a nettle, though not one I’d seen in the guide.

Querying “nettle”, I quickly got an image that led me to identification: the red (or purple) dead-nettle. It’s a plant from Eurasia that has established itself here.

Having identified the plant, I checked the field guide’s index for it; indeed, it’s in there, though without a picture. It’s mentioned in a paragraph as related to the common dead-nettle.

I’m excited about this identification, and will be sharing more as they evolve.



Pojar, Jim and Andy MacKinnon. Plants of Coastal British Columbia. Vancouver:
  BC Ministry of Forests and Lone Pine Publishing, 1994.

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Consumer electronics: the PNY flash drive

The tutor tells of a purchase he made.

A few weeks back, one of my kids wanted to borrow a flash drive so he could load his project on it to take to school. We didn’t have any at our fingertips convenient to lend; each that I knew of already contained files we didn’t want to lose. My wife eventually found him one that had been given to her for a purpose served many years ago. I resolved, however, to buy each of the kids one of their own.

Surprisingly, it’s been years since I bought a flash drive. Lots of files, nowadays, are simply uploaded to email, or some other server, then downloaded elsewhere as needed. I seldom use computers outside my home, so hardly ever use a flash drive. I was expecting to buy a couple of 2GB drives, paying around 1$ per GB.

At Staples today, the smallest flash drive I noticed was 8GB. I figured that was much more than a student would need, so began looking at the 8GB options. However, a PNY box caught my eye: two 16GB drives for $10.97. Was this too good to be true? I asked the clerk; she said it wasn’t the most recognized brand of flash drive, so might be less expensive just for that reason. What she said seemed true to me; I’d never heard of PNY. Turning the box over, I read “ASSEMBLED IN THE USA”. I decided to buy it.

At home, I opened the box and removed the two small flash drives. From my phone, via the desktop computer, I loaded a photo onto each one to see if they both worked, which they did. The load time seems fast to me.

It turns out PNY is a consumer electronics firm based in Parsippany, New Jersey.

I’ll be sharing more consumer electronics discoveries:)

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Lifestyle: bird identification from field guide: rufous-sided towhee

The tutor shares another backyard bird identification.

Similarly with Audubon’s warbler (see my post about it here), I could only identify the rufous-sided towhee through the binoculars. I heard the call, detected flitting in a hedgerow, then raised the binoculars to it.

I’ve never noticed a rufous-sided towhee before; from the reading, they’re quite common. The bird was handsome, with a glossy white breast, red side, and the rest black. His wings were spotted with white.

The rufous-sided towhee has a distinct call; I haven’t heard him since yesterday afternoon. I’m sure he’ll be back:)


Robbins, Chandler S. et al. Birds of North America: A Guide to Field Identification.
   New York: Golden Press, 1966.

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Calculus: the limit, as n tends to infinity, of nth root of n.

The tutor works a limit using the log trick and l’Hôpital’s rule.

Example: Evaluate lim_{n \rightarrow \infty} \sqrt[n]{n}


First, imagine

    \[y=lim_{n \rightarrow \infty} \sqrt[n]{n}\]

Next, we take the logarithm of both sides:

    \[lny=ln(lim_{n \rightarrow \infty} \sqrt[n]{n})\]

Now, because both lny and \sqrt[n]{n} are continuous as y, n \rightarrow \infty, we can change their order on the right side:

    \[lny=lim_{n \rightarrow \infty} ln\sqrt[n]{n}\]

Changing the radical to an exponent, we get

    \[lny=lim_{n \rightarrow \infty} ln\ n^{\frac{1}{n}}\]

Using the log rule about exponent-to-multiple gives

    \[lny=lim_{n \rightarrow \infty} \frac{1}{n}ln\ n\]


    \[lny=lim_{n \rightarrow \infty} \frac{ln\ n}{n}\]

This limit has the \frac{\infty}{\infty} form, which means, by l’Hôpital’s Rule, we can take the derivative of the numerator and denominator separately, then take the limit of that result:

    \[lny=lim_{n \rightarrow \infty} \frac{\frac{1}{n}}{1}=\frac{0}{1}=0\]


    \[lny = 0\]

We take the exponential of both sides:

    \[e^{lny} = e^0\]

to arrive at


Recalling that y=lim_{n \rightarrow \infty} \sqrt[n]{n}, we realize that

    \[lim_{n \rightarrow \infty} \sqrt[n]{n}=1\]




Larson, Roland E. and Robert P. Hostetler. Calculus. Toronto:
   D.C. Heath and Company, Ltd., 1986.

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.