Numbers

1. Integers
Natural Numbers: { 1, 2, 3, 4, 5, …} or Counting Numbers
Whole Numbers: {0, 1, 2, 3, 4, 5,…}
Integers: {… -4, -3, -2, -1, 0, 1, 2, 3, 4, }Includes positive numbers and negative numbers.
Also the neutral number zero
Number Line
Absolute Value: A number’s distance from zero on a number line
Real Numbers. The set of all numbers that can be represented by points on a number line.
Rational Number. Is a real number that can be expressed as the ratio of two integers {n/m}
 Rational numbers are whole numbers, fractions, and decimals )
Irrational Number. Is a real number that is not a rational number (it cannot be expressed as the ratio of two integers)

Comparing numbers

 



Operations with Signed Numbers

Addition.
  • If the signs of the numbers are the same, ADD. The answer has the same sign.
  • If the signs of numbers are different, SUBTRACT. The answer has the sign of the larger number.
Subtraction. Change subtraction to addition of the opposite number.
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Add_ and_Subtract_Integers

Addition and Subtraction of Signed Numbers

Adding, Subtracting Integers Help

 

Multiplication and Division. Multiply or Divide.
If the numbers have the same sign the answer is POSITIVE.
If the numbers have different signs the answer is NEGATIVE.

Multiply_and_Divide_Integers

Prime Numbers. Numbers that can only be divided by 1 and itself and have no remainders.

Prime Numbers = 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43,

Composite Numbers. Numbers that can be divided by more than two factors and have no remainders.

Composite Numbers = 4, 6, 8, 10, 12, 14, 16, 18, 20, .

Neutral Numbers. These numbers are not prime nor composite: 0 and 1

Rounding Numbers.
(1) Underline the number that is in the place that you want to round
(2) Look at the number on the right of the underlined number.
* If it’s 5 or more, add one more to the underlined number.
* If it’s 4 or less, keep the underlined number the same.

(3) Numbers on the left stay the same and numbers on the right became zeros.


Ex. Round to the nearest hundreds

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Rounding whole numbers (to the nearest ten, hundred, thousand)

Powers of 10

Powers of 10 can be written in two ways:

• With an exponent: 10³

• In expanded form: 1000  (1000 = 10³, note that the number of zeros is equivalent to the exponent)

Powers of 10

 

Multiplying by a positive power of 10 makes the number larger and multiplying by a negative power of 10 makes the number smaller.

5 x 10¹= 5 x 10 = 50

5 x 10²= 5 x 100 = 500

5 x 10³= 5 x 1,000 = 5,000

5 x 10⁴= 5 x 10,000 = 50,000

To multiply a whole number by a power of ten, just count how many zero you have and attach that to the whole number.

 

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Multiply By Powers of 10

To divide by a power of 10, simply move the decimal point to the left the same number of places as the exponent or as the number of zeros.  Example:

50 / 10¹= 50/10 = 5

500/10² = 500/100 = 5

5000/10³ = 5000/1000 = 5

Note: The decimal point of a whole number is always to the right of the one’s place.

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Divide By Powers of 10

 

Positive, negative and zero exponents with a base of ten

10000 = 1 x 10⁴
1000 = 1 x 10³
100 = 1 x 10²
10 = 1 x 10ᴵ
1 = 10⁰
1/10 = 0.1 = 1 x 10⁻ᴵ
1/100 = 0.01 = 1 x 10⁻²
1/1000 = 0.001 = 1 x 10⁻³

1/10000 = 0.0001 = 1 x 10⁻⁴

When we multiply a number by a positive power of 10, we move the decimal point of the number to the right.

When we multiply a number by a negative power of 10, we move the decimal point of the number to the left.

The number of places to move would be equal to the power of ten.

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 Multiply and divide by positive powers of Ten

 

Place Value. It’s determined by its position with respect to the decimal point.
Place Value
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Place Value of Whole Numbers

Compare and order Integers

We can compare different integers by looking at their positions on the number line. For any two different places on the number line, the integer on the right is greater than the integer on the left.
Ex. Order 3, 5, -3, 1, -5

Compare

When we compare whole numbers we line up place values (so that similar place values are lined up). Start at the left and find the first place where the digits differ.

Example: To compare the numbers 1,245,214 and 1,236,789, we will line up the numbers so the digits in the ones place line up.

Compare

 

 

 

 

Since 4 > 3,    We conclude that 1,245,214 is bigger than 1,236,789

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Comparing Integers

Comparing Vocabulary

Comparing Symbols Help

Comparing Writing

 

Standard decimal notation (base 10 notation)

Base 10 refers to the numbering system in common use.  When you write “316”, the “3” means 300, the “1” means 10, and the “6” means 6.

This can be written 316 = 3*10² + 1*10¹ + 6*10⁰

Expanded notation

Method of writing numbers as the sum of powers of ten or as the sum of its units, tens, hundreds, etc.

Example: 316 = 3 x 100 + 1 x 10 + 6 =300 + 10 + 6

Scientific notation

Scientific notation is a way of writing numbers too large or small to be conveniently written in standard decimal notation.

For example, instead of writing 65,000,000, we write 6.5 x 10⁷

 

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Scientific Notation

Standard Form

Scientific Notation B 

Standard Form B 

 

 

 

 

 

 

 

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