1. Thursday, October 6, 2016
2.1 Rational Numbers

2. rational number - a number that can be expressed as a fraction; a terminating or repeating decimal
irrational number – a number that can’t be written as a fraction; a non-terminating, non-repeating decimal
terminate – to stop

3. Just listen and learn... Irrational Numbers Real Numbers Whole 0
½, -½, 7¾, 4.9, -6.27
Irrational Numbers
Natural 1,2, 3, ...
Whole 0
Integers
...-3, -2, -1, ...

4. Number Groups natural (N): 1, 2, 3, 4, ... (counting numbers)
Resume writing…
Number Groups
natural (N): 1, 2, 3, 4, ... (counting numbers)
whole (W): 0, 1, 2, 3, ... (counting numbers and 0)
integer (Z): ..., –2, –1, 0, 1, 2, ...( + and ‒ wholes)
rational (Q): fractions
irrational (I): non-terminating and non-repeating
real (R): rationals and irrationals

5. A) Which, if any, of the following are equal?
Write in these forms only.

6. B) Order from least to greatest.
Methods to consider:
Common sense (be careful!) .
Change all numbers to decimals (usually the best).
Change all numbers to fractions with com denoms.
Strategies:
All negatives are less than all positives.
Numbers that are more negative are smaller.
Arrange negatives first, then positives, then together.

7. B) Order from least to greatest.

8. Let’s categorize some numbers…

9. Least Common Denominator (LCD) – the LCM of two or more denominators.
Least Common Multiple (LCM) – the smallest common product of a group of numbers
► LCM is  given numbers
Least Common Denominator (LCD) – the LCM of two or more denominators.
Do not just multiply denominators. This does not always give LCD.
C) Find the LCD of 3
Use side and bottom numbers.
LCD= 3(2)(5) = 30

10. D) Find the LCD of . 2 8 14 42 7 4 7 21 4 1 3 LCM: 2(7)(4)(1)(3) = 168
If factor divides only 2 of 3 numbers, proceed and bring down 3rd number. 7
LCM: 2(7)(4)(1)(3) = 168

11. 3 3 12 5 1 4 5 LCD: 3(1)(4)(5) = 60 E) Simplify. 40 55 36
To add fractions, you must have an LCD.
An LCD can be found mentally, but use this process if you can’t. 40 55 36 3
LCD: 3(1)(4)(5) = 60