1 Exponential Notation Preface This mathematics practice book for M.4 has been developed for English reading skills, with learning contents. It is aimed at guiding students and directing students to obtain the essential knowledge for reading mathematics skill. The content knowledge including Simplifying Fractions, Prime or Composite?, Exponential Notation, and Converting Fractions to Decimals are also focused on. The teaching and learning guidelines presented in this practice book lend the characteristic of learning development through mathematical processes. The focus on conceptual development using mathematics content linked to reading skill development and using mathematical processes in answering the questions from reading. This mathematics practice book consists of 4 units. The contents are introduced with some revision and linkages with the existing understanding so that the students would systematically learn. Teachers should also provide additional exercises to further develop students’ skills. In addition to supporting students in the content knowledge state in the reading skill, this mathematics practice book also helps promote students to have sufficient knowledge in mathematics reading, while developing the ability to use mathematics as a tool for learning and studying higher levels of mathematics. Somchai Ponchai
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Exponential Notation · 2014-10-27 · Exponential Notation 1 Preface This mathematics practice book for M.4 has been developed for English reading skills, with learning contents.
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1 Exponential Notation
Preface
This mathematics practice book for M.4 has been developed for English reading skills, with learning contents. It is aimed at guiding students and directing students to obtain the essential knowledge for reading mathematics skill. The content knowledge including Simplifying Fractions, Prime or Composite?, Exponential Notation, and Converting Fractions to Decimals are also focused on.
The teaching and learning guidelines presented in this practice book lend the characteristic of learning development through mathematical processes. The focus on conceptual development using mathematics content linked to reading skill development and using mathematical processes in answering the questions from reading. This mathematics practice book consists of 4 units. The contents are introduced with some revision and linkages with the existing understanding so that the students would systematically learn. Teachers should also provide additional exercises to further develop students’ skills.
In addition to supporting students in the content knowledge state in the reading skill, this mathematics practice book also helps promote students to have sufficient knowledge in mathematics reading, while developing the ability to use mathematics as a tool for learning and studying higher levels of mathematics.
The exponential notation (sometimes called the "scientific" notation) greatly simplifies calculations, especially with very large and very small numbers. It uses positive and negative exponents to write multiples and submultiples of 10:
1000 = 10 x 10 x 10 = 103
100 = 10 x 10 = 102
10 = 10 = 101
1 = 100
0.1 = 1/10 = 10-1
0.01 = 1/100 = 10-2
0.001 = 1/1000 = 10-3>
Note that for numbers greater than one, "l0p" represents the number "l" followed by p zeros. For negative exponents, the notation 10-p represents a fractional number, with the digit "1" occupying the pth decimal place to the right of the decimal point. This idea may he extended to any number, for any number may be written as a multiple of a power of ten. For example, the number 4000 may he written as 4 x 103. The number 0.038 may be written as 3.8 x 10-2. These numbers have two parts, the numeric part (3.8) and the exponential part (10-2). Interpretation of these numbers is easy if you note that they may be converted back to ordinary notation by simply shifting the decimal point of the numeric part a number of places equal to the value of the exponent. To remove the exponential part of 3.8 x 10-2, simply move the decimal point of 3.8 two places to the left and it becomes 0.038 again. Numbers may be written in many equivalent exponential forms. Simply bserve the rule: When the exponent is increased by amount p, the decimal of the numeric part must be shifted p places to the left to compensate. When the exponent is decreased by amount p, the decimal of the numeric part must be shifted p places to the right. This rule need not be committed to memory, for the mathematical "common sense" you have acquired in other courses should allow you to "derive" the rule as needed, and the reinforcement of frequent use will soon make it a habit.
A conventional style for expressing results makes maximum use of the space-saving economy of this notation. Write all results so that there's only one significant digit to the left of the decimal point in the numeric part. This is called "standard form". When standard form is used there will be no trailing zeros to the right of the last significant digit. So there's never any doubt how many figures are significant. Numbers expressed in exponential notation may be easily multiplied or divided by operating on the numeric and exponential parts separately. We utilize the fact that multiplication is commutative. One realistic, non-trivial example should demonstrate the process: (3×10-8)(2.4×105)(6×102)/4×109 = 3(2.4)6/4 × (10-8 × 105 × 102) / 4×109 = 10.8×10(-8+5+2-9) = 10.8×10-10 Numbers in exponential notation may be easily raised to powers by applying the usual rules.
(AB)p = ApBp and (Xp)q = Xpq Example: (12 x 103)2 = 122 x 106 = 144 x 106 = 1.44 x 108 The rules given for multiplication and division of numbers in exponential notation must not be applied to addition or subtraction. It is necessary to convert both numbers to the same power of 10 before adding them. Example: (3 x 105) + (2 x 107) = (3 x 105) + (200 x 105) = 203 x 105
Scientific Notation Scientific Notation (also called Standard Form in Britain) is a special way of writing numbers:
It makes it easy to use big and small values. OK, How Does it Work?
Example: 700 Why is 700 written as 7 × 102 in Scientific Notation ? 700 = 7 × 100 and 100 = 102 so 700 = 7 × 102 Both 700 and 7 × 102 have the same value, just shown in different ways.
Example: 4,900,000,000 1,000,000,000 = 109 , so 4,900,000,000 = 4.9 × 109 in Scientific Notation The number is written in two parts: Just the digits (with the decimal point placed after the first digit), followed by × 10 to a power that puts the decimal point where it should be (i.e. it shows how many places to move the decimal point).
In this example, 5326.6 is written as 5.3266 × 103, because 5326.6 = 5.3266 × 1000 = 5.3266 × 103 Other Way of Writing It Sometimes people use the ^ symbol (above the 6 on your keyboard), as it is easy to type. Example: 3 × 10^4 is the same as 3 × 104 3 × 10^4 = 3 × 10 × 10 × 10 × 10 = 30,000 How to Do it
To figure out the power of 10, think "how many places do I move the decimal point?"
Example: 0.0055 would be written as 5.5 × 10-3 Because 0.0055 = 5.5 × 0.001 = 5.5 × 10-3
Example: 3.2 would be written as 3.2 × 100 We didn't have to move the decimal point at all, so the power is 100 But it is now in Scientific Notation Check! After putting the number in Scientific Notation, just check that: The "digits" part is between 1 and 10 (it can be 1, but never 10) The "power" part shows exactly how many places to move the decimal point
When the number is 10 or greater, the decimal point has to move to the left, and the power of 10 will be positive.
When the number is smaller than 1, the decimal point has to move to the right, so the power of 10 will be negative:
Why Use It? Because it makes it easier when you are dealing with very big or very small numbers, which are common in Scientific and Engineering work. Example: it is easier to write (and read) 1.3 × 10-9 than 0.0000000013 It can also make calculations easier, as in this example: Example: a tiny space inside a computer chip has been measured to be 0.00000256m wide, 0.00000014m long and 0.000275m high. What is its volume? Let's first convert the three lengths into scientific notation: width: 0.000 002 56m = 2.56×10-6
length: 0.000 000 14m = 1.4×10-7
height: 0.000 275m = 2.75×10-4 Then multiply the digits together (ignoring the ×10s): 2.56 × 1.4 × 2.75 = 9.856 Last, multiply the ×10s: 10-6 × 10-7 × 10-4 = 10-17 (easier than it looks, just add -6, -4 and -7 together) The result is 9.856×10-17 m3 It is used a lot in Science:
Example: Suns, Moons and Planets The Sun has a Mass of 1.988 × 1030 kg. It would be too hard for scientists to have to write 1,988,000,000,000,000,000,000,000,000,000 kg Engineering Notation Engineering Notation is like Scientific Notation, except that you only use powers of ten that are multiples of 3 (such as 103, 10-3, 1012 etc). Example: 19,300 would be written as 19.3 × 103 Example: 0.00012 would be written as 120 × 10-6 Notice that the "digits" part can now be between 1 and 1,000 (it can be 1, but never 1,000). The advantage is that you can replace the ×10s with Metric Numbers. So you can use standard words (such as thousand or million) prefixes (such as kilo, mega) or the symbol (k, M, etc) Example: 19,300 meters would be written as 19.3 × 103 m, or 19.3 km
exponential /ˌek.spə ʊ ˈnen. t ʃ ə l/ /-spoʊ-/ adjective INCREASE formal describes a rate of increase which becomes quicker and quicker as the thing that
increases becomes larger There has been an exponential increase in the world population this century.
notation /nə ʊ ˈteɪ.ʃ ə n/ /noʊ-/ noun [ C or U ] a system of written symbols used especially in mathematics or to represent musical notes musical/scientific notation Did you write things out in standard notation?
decimal /ˈdes.ɪ.məl/ noun [ C ] ( specialized decimal fraction ) a number expressed using a system of counting based on the number ten Three fifths expressed as a decimal is 0.6.
integer /ˈɪn.tɪ.dʒə r / /-dʒɚ/ noun [ C ] specialized a whole number and not a fraction The numbers -5, 0 and 3 are integers.
relationship /rɪˈleɪ.ʃ ə n.ʃɪp/ noun [ C ] CONNECTION the way in which two things are connected Scientists have established the relationship between lung cancer and smoking.
base /beɪs/ noun MATHEMATICS [ C usually singular ] specialized the number on which a counting system is built A binary number is a number written in base 2, using the two numbers 0 and 1.
regularly /ˈreg.jʊ.lə.li/ /-lɚ-/ adverb Accidents regularly occur on this bend. The competitors set off at regularly spaced intervals.
exponent /ɪkˈspəʊ.nənt/ /-ˈspoʊ-/ noun [ C ] NUMBER specialized a number or sign which shows how many times another number is to be multiplied by
itself In 6 4 and y n , 4 and n are the exponents.
standard /ˈstæn.dəd/ /-dɚd/ noun QUALITY [ C or U ] a level of quality This essay is not of an acceptable standard - do it again. This piece of work is below standard/is not up to standard.
allow /əˈlaʊ/ verb GIVE PERMISSION [ T ] to make it possible for someone to do something, or to not prevent something from happening;
give permission [ + to infinitive ] Do you think Dad will allow you to go to Jamie's party? You're not allowed to talk during the exam. Her proposals would allow (= make it possible for) more people to stay in full-time education.
Write the letter of the correct match next to each word.
Exponential notation is one way to write a very large or very small number. The number is written as the product of either a decimal or an integer and as a power of 10. This works because of the way our base-10 place value system is set up. Each place value column is 10 times larger than the one before it as you move from right to left. When moving from left to
right, each place value column is ten times smaller than the one before it. This “times 10” relationship between the columns lets us show numbers in exponential notation. The base number 10 is written as a regularly sized number. An exponent is a small number written up and to the right of the 10. The exponent tells how many place value columns are being shown. The number 10 can be shown as 1 x 101. This is like saying 1 x 10. The number 100 can be shown as 1 x 102. This is like saying 1 x 10 x 10. The number 1,000 can be shown as 1 x 103. This is like saying 1 x 10 x 10 x 10. The number 10,000 can be shown as 1 x 104. This is like saying 1 x 10 x 10 x 10 x 10. For each place value column, add one more number to the exponent. So far, our multiplier has been 1. It can be another whole number, like 4. The number 4,000,000 can be shown in exponential notation as 4 x 106. This is a shorter way of saying 4 x 10 x 10 x 10 x 10 x 10 x 10. The exponent matches the number of zeroes on the original number. The multiplier can even be a decimal. Be careful when you change the number 4.5 x 104 from exponential to standard notation. Standard notation is writing the number in regular number form. The number 4.5 x 104 becomes not 450,000 but rather 45,000. There are only three zeros in the correct answer. The decimal point replaces one of the zeros.
Answer the following questions based on the reading passage. Don’t forget to go back to the passage whenever necessary to find or confirm your answers. 1) How would you write 60,000 in exponential notation? ____________________________________________________ ____________________________________________________ 2) When do you think it would make sense to write a number using exponential notation? ____________________________________________________ ____________________________________________________ 3) How many zeros would you expect to see when writing the standard notation for the number 9 x 108? ____________________________________________________ ____________________________________________________ 4) What is the relationship between each of the place value columns? ____________________________________________________ ____________________________________________________ 5) What is an exponent? ____________________________________________________ ____________________________________________________
While reading, I found it easiest to …………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
I’m proud of my answer to question …………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….
In the ………… section because ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….
1. b 2. d 3. c 4. b 5. c 6. c 7. b 8. a 9. a 10. d
1. e 2. g 3. d 4. f 5. h 6. c 7. a 8. b 9. i Actual wording of answers may vary. 1. 6×104
2. when a number is very long. 3. 8 4. They have a difference of 10. 5. The small number to the right of the base number that tells how many place value columns are being shown.
1. d 2. b 3. c 4. c 5. b 6. c 7. a 8. b 9. d 10. a