



The steps are summarized below.
Convert scientific notation to decimal form.
To convert scientific notation to decimal form:
 Determine the exponent,
$n$ , on the factor 10.
 Move the decimal
$n$ places, adding zeros if needed.
 If the exponent is positive, move the decimal point
$n$ places to the right.
 If the exponent is negative, move the decimal point
$\leftn\right$ places to the left.
 Check.
Multiply and divide using scientific notation
Astronomers use very large numbers to describe distances in the universe and ages of stars and planets. Chemists use very small numbers to describe the size of an atom or the charge on an electron. When scientists perform calculations with very large or very small numbers, they use scientific notation. Scientific notation provides a way for the calculations to be done without writing a lot of zeros. We will see how the Properties of Exponents are used to multiply and divide numbers in scientific notation.
Multiply. Write answers in decimal form:
$\left(4\phantom{\rule{0.2em}{0ex}}\times \phantom{\rule{0.2em}{0ex}}{10}^{5}\right)\left(2\phantom{\rule{0.2em}{0ex}}\times \phantom{\rule{0.2em}{0ex}}{10}^{\mathrm{7}}\right).$
Solution
$\begin{array}{cccc}& & & \left(4\phantom{\rule{0.2em}{0ex}}\times \phantom{\rule{0.2em}{0ex}}{10}^{5}\right)\left(2\phantom{\rule{0.2em}{0ex}}\times \phantom{\rule{0.2em}{0ex}}{10}^{\mathrm{7}}\right)\hfill \\ \\ \\ \text{Use the Commutative Property to rearrange the factors.}\hfill & & & 4\xb72\xb7{10}^{5}\xb7{10}^{\mathrm{7}}\hfill \\ \\ \\ \text{Multiply.}\hfill & & & 8\phantom{\rule{0.2em}{0ex}}\times \phantom{\rule{0.2em}{0ex}}{10}^{\mathrm{2}}\hfill \\ \\ \\ \text{Change to decimal form by moving the decimal two places left.}\hfill & & & 0.08\hfill \end{array}$
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Multiply
$\left(3\phantom{\rule{0.2em}{0ex}}\times \phantom{\rule{0.2em}{0ex}}{10}^{6}\right)\left(2\phantom{\rule{0.2em}{0ex}}\times \phantom{\rule{0.2em}{0ex}}{10}^{\mathrm{8}}\right)$ . Write answers in decimal form.
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Multiply
$\left(3\phantom{\rule{0.2em}{0ex}}\times \phantom{\rule{0.2em}{0ex}}{10}^{\mathrm{2}}\right)\left(3\phantom{\rule{0.2em}{0ex}}\times \phantom{\rule{0.2em}{0ex}}{10}^{\mathrm{1}}\right)$ . Write answers in decimal form.
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Divide. Write answers in decimal form:
$\frac{9\phantom{\rule{0.2em}{0ex}}\times \phantom{\rule{0.2em}{0ex}}{10}^{3}}{3\phantom{\rule{0.2em}{0ex}}\times \phantom{\rule{0.2em}{0ex}}{10}^{\mathrm{2}}}.$
Solution
$\begin{array}{cccc}& & & \frac{9\phantom{\rule{0.2em}{0ex}}\times \phantom{\rule{0.2em}{0ex}}{10}^{3}}{3\phantom{\rule{0.2em}{0ex}}\times \phantom{\rule{0.2em}{0ex}}{10}^{\mathrm{2}}}\hfill \\ \\ \\ \text{Separate the factors, rewriting as the product of two fractions.}\hfill & & & \frac{9}{3}\phantom{\rule{0.2em}{0ex}}\times \phantom{\rule{0.2em}{0ex}}\frac{{10}^{3}}{{10}^{\mathrm{2}}}\hfill \\ \\ \\ \text{Divide.}\hfill & & & 3\phantom{\rule{0.2em}{0ex}}\times \phantom{\rule{0.2em}{0ex}}{10}^{5}\hfill \\ \\ \\ \text{Change to decimal form by moving the decimal five places right.}\hfill & & & \mathrm{300,000}\hfill \end{array}$
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Divide
$\frac{8\phantom{\rule{0.2em}{0ex}}\times \phantom{\rule{0.2em}{0ex}}{10}^{4}}{2\phantom{\rule{0.2em}{0ex}}\times \phantom{\rule{0.2em}{0ex}}{10}^{\mathrm{1}}}$ . Write answers in decimal form.
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Divide
$\frac{8\phantom{\rule{0.2em}{0ex}}\times \phantom{\rule{0.2em}{0ex}}{10}^{2}}{4\phantom{\rule{0.2em}{0ex}}\times \phantom{\rule{0.2em}{0ex}}{10}^{\mathrm{2}}}$ . Write answers in decimal form.
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Key concepts

Property of Negative Exponents
 If
$n$ is a positive integer and
$a\ne 0$ , then
$\frac{1}{{a}^{\text{\u2212}n}}={a}^{n}$

Quotient to a Negative Exponent
 If
$a,b$ are real numbers,
$b\ne 0$ and
$n$ is an integer , then
${\left(\frac{a}{b}\right)}^{\text{\u2212}n}={\left(\frac{b}{a}\right)}^{n}$

To convert a decimal to scientific notation:
 Move the decimal point so that the first factor is greater than or equal to 1 but less than 10.
 Count the number of decimal places,
$n$ , that the decimal point was moved.
 Write the number as a product with a power of 10. If the original number is:
 greater than 1, the power of 10 will be
${10}^{n}$
 between 0 and 1, the power of 10 will be
${10}^{\text{\u2212}n}$
 Check.

To convert scientific notation to decimal form:
 Determine the exponent,
$n$ , on the factor 10.
 Move the decimal
$n$ places, adding zeros if needed.
 If the exponent is positive, move the decimal point
$n$ places to the right.
 If the exponent is negative, move the decimal point
$\leftn\right$ places to the left.
 Check.
Questions & Answers
How do you find divisible numbers without a calculator?
When she graduates college, Linda will owe $43,000 in student loans. The interest rate on the federal loans is 4.5% and the rate on the private bank loans is 2%. The total interest she owes for one year was $1,585. What is the amount of each loan?
Sean took the bus from Seattle to Boise, a distance of 506 miles. If the trip took 7 2/3 hours, what was the speed of the bus?
How did you work it out?
Esther
s=mi/hr 2/3~0.67 s=506mi/7.67hr = ~66 mi/hr
Orlando
hello, I have algebra phobia. Subtracting negative numbers always seem to get me confused.
what do you need help in?
Felix
subtracting a negative....is adding!!
Heather
look at the numbers if they have different signs, it's like subtracting....but you keep the sign of the largest number...
Felix
for example.... 19 + 7.... different signs...subtract.... 12 keep the sign of the "largest" number 19 is bigger than 7.... 19 has the negative sign... Therefore, 12 is your answer...
Felix
Thanks Felix.l also get confused with signs.
Esther
Thank you for this
Shatey
think about it like you lost $19 (19), then found $7(+7). Totally you lost just $12 (12)
Annushka
I used to struggle a lot with negative numbers and math in general what I typically do is look at it in terms of money I have $5 in my account I then take out 5 more dollars how much do I have in my account well$10 ... I also for a long time would draw it out on a number line to visualize it
Meg
practicing with smaller numbers to understand then working with larger numbers helps too and the song/rhyme
same sign add and keep opposite signs subtract keep the sign of the bigger # then you'll be exact
Meg
Bruce drives his car for his job. The equation R=0.575m+42 models the relation between the amount in dollars, R, that he is reimbursed and the number of miles, m, he drives in one day. Find the amount Bruce is reimbursed on a day when he drives 220 miles
john is 5years older than wanjiru.the sum of their years is27years.what is the age of each
john is 16. wanjiru is 11.
Felix
275=22
22÷2=11
11+5=16
Joyce
I don't see where the answers are.
Ed
Cindy and Richard leave their dorm in Charleston at the same time. Cindy rides her bicycle north at a speed of 18 miles per hour. Richard rides his bicycle south at a speed of 14 miles per hour. How long will it take them to be 96 miles apart?
18t+14t=96
32t=96
32/96
3
Christopher
show that a^nb^2n is divisible by ab
What does 3 times your weight right now
Use algebra to combine 39×5 and the half sum of travel of 59+30
Cherokee
What is the segment of 13? Explain
Cherokee
my weight is 49. So 3 times is 147
Cherokee
kg to lbs you goin to convert 2.2 or one if the same unit your going to time your body weight by 3. example if my body weight is 210lb. what would be my weight if I was 3 times as much in kg. that's you do 210 x3 = 630lb. then 630 x 2.2= .... hope this helps
tyler
How to convert grams to pounds?
paul
How many numbers each equal to y must be taken to make 15xy
find the equation whose roots are 1 and 2
(x  2)(x 1)=0
so equation is x^2x+2=0
Ranu
I believe it's x^23x+2
NerdNamedGerg
because the X's multiply by the 2 and the 1 and than combine like terms
NerdNamedGerg
find the equation whose roots are 1 and 4
Adda
find the equation whose roots are 2 and 1
Adda
(×+1)(×4)
= x^23×4
Gee
Quadratic equations involving factorization
there's a chatting option in the app wow
Nana
Nice to meet you all
Nana
Hey you all there are several Free Apps that can really help you to better solve type Equations.
Debra
Debra, which apps specifically. ..?
Nana
am having a course in elementary algebra ,any recommendations ?
samuel
Samuel Addai, me too at ucc
elementary algebra as part of my core subjects in science
Nana
me too as part of my core subjects in R M E
Ken
at ABETIFI COLLEGE OF EDUCATION
Ken
ok great. Good to know.
Joan
5x  3x = 1/2  1/3
2x = 1/6
x = 1/12
Ranu
Please help me solve this 10x+14=2x+38
Erica
the previous equation should be
3x = 1/6
x=1/18
Sriram
for the new one
10x + 2x = 38  14
Sriram
10x + 14 = 2x +38
10x + 2x = 38  14
12x = 24
divide both sides by the coefficient of x, which is 12
therefore × = 2
vida
a trader gains 20 rupees loses 42 rupees and then gains ten rupees Express algebraically the result of his transactions
a trader gains 20 rupees loses 42 rupees and then gains 10 rupees Express algebraically the result of his three transactions
vinaya
a trader gains 20 rupees loses 42 rupees and then gains 10 rupees Express algebraically the result of his three transactions
vinaya
a trader gains 20 rupees loses 42 rupees and then gains 10 rupees Express algebraically the result of his three transactions
vinaya
Source:
OpenStax, Elementary algebra. OpenStax CNX. Jan 18, 2017 Download for free at http://cnx.org/content/col12116/1.2
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