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Section 15.2 Scientific Notation Activities

Example 15.2.1.

Consider the meme below, which made its way around the internet in the mid-2010s:
Powerball 1.3 billion divided by US pop 300 million = 4.33 mil per person
Powerball 1.3 billion divided by US pop 300 million = 4.33 mil per person. Poverty solved!
Figure 15.2.2. Powerball Math
This meme spread so far in part because the math is wrong! Writing the numbers in scientific notation can help:
\begin{align*} 1.3\text{ billion} \amp = 1.3 \times 10^9\\ 300\text{ million} \amp = 3 \times 10^8\\ \frac{1.3\text{ billion}}{300\text{ million}} \amp = \frac{1.3 \times 10^9}{3 \times 10^8}\\ \amp =\frac{1.3}{3} \times \frac{10^9}{10^8}\\ \amp = 0.433 \times 10\\ \frac{1.3\text{ billion}}{300\text{ million}} \amp = 4.33 \end{align*}
That is, dividing a $1.3 billion powerball jackpot among a US population of 300 million would give everyone $4.33. This will not solve poverty.
Notice that writing 1.3 billion and 300 million in scientific notation meant that we didn’t need to enter long strings of zeros into our calculator. This is an advantage, since it is very easy to accidentally include too many or too few zeros!

Example 15.2.3.

Let’s use scientific notation to help us estimate the number of words in War and Peace as millions, billions, trillions, or some other size. Using an internet search, we found that sample pages of an e-book version of War and Peace have about 300 words on each page. This e-book version is 1307 pages long.
The number of words in War and Peace can be estimated as
\begin{align*} \text{Words} \amp= \text{Pages} \times \frac{\text{Words}}{\text{Pages}}\\ \amp= 1307 \times 300\\ \amp (1.307 \times 10^3)(3 \times 10^2)\\ \amp (1.307 \times 3) \times (10^3 \times 10^2)\\ \amp (3\text{ish}) \times 10^5 \end{align*}
Since \(10^5\) is hundreds of thousands, this tells us that a rough estimate for the number of words in War and Peace is 300 thousand.

Activity 15.2.1.

Use scientific notation to estimate:

(a)

The amount of money needed to send all adults in the United States to a public college for four years. Assume there are about 258 million adults in the United States and that the cost of tuition and fees to a public college is about $25,000.

(b)

The number of seconds you have been alive if you are 20 years old.

(c)

The amount of money needed per year to raise wages in the US to $15 per hour. Assume that there are 800 thousand full-time US workers making the federal minimum wage of $7.25 or less
 1 
and that a full-time worker works 40 hours a week for 50 weeks a year. Hint: How much do we need to raise each worker’s hourly wage?

(d)

If the U.S. national debt was $36 trillion in June of 2025 and was evenly divided among the 342 million people living in the United States in 2025, estimate how much each person’s share would be.

(e)

The US federal budget
 2 
was about $7.266 trillion in 2025.
(ii)
What percentage of the budget would be needed to pay for your estimate in part (c), for raising the minimum wage to $15 per hour?

Activity 15.2.2.

Below is a table that describes some small numbers in standard decimal notation, and scientific notation. Notice that for small numbers:
  • Scientific notation keeps track of the number of decimal places to the left of the second nonzero digit, but after the decimal point, using the exponent.
  • The exponent is negative
Table 15.2.4. Examples of Scientific Notation (Large Numbers)
β€œRegular” Notation Scientific Notation Number of places the decimal point was moved
\(0.1221\) \(1.221 \times 10^{-1}\) 1
\(0.01045\) \(1.045 \times 10^{-2}\) 2
\(0.0003475\) \(3.475 \times 10^{-4}\) 4
\(0.000 000 1472\) \(1.472 \times 10^{-7}\) 7

(a)

Write a sentence in your words that explains how to convert a small number in β€œregular” notation into scientific notation.

(c)

Write a sentence in your own words describin how to convert a number from scientific notation into β€œregular” notation (without using a calculator).

Activity 15.2.3.

If you type \(\frac{56}{10^{9}}\) into Google, you will get:
5.6e-8
\(56\) divided by \(10^{-9}\) equals 5.6 e -8.
Figure 15.2.5. Strange Calculator Notation
This notation may look strange, but it is how many calculators write \(5.6 \times 10^{-8}\text{.}\) It may be helpful to think of the β€œe” as standing for β€œexponent”.
Write each of the calculator outputs shown below in scientific notation and standard decimal notation.
5e-7, 6.08e-8, 9e+15
5e-7, 6.08234793e-8, 8.99996e+15
Figure 15.2.6. More Strange Calculator Notation