Week 7 - Rational Numbers Flashcards
Rational Numbers
Rational numbers are all integers, fractions,
repeating decimals and terminating decimals.
They’re any number that can be written in the form a/b
Where a and b are whole numbers but b is not equal to zero
Fractions
Define
3/5 what does it mean example
Any part of a group, number or whole.
3/5 = 3 fifths
Divide a unit length into 5 equal parts and take 3 of these parts
Different representation of rational numbers
F
D
P
Fractions: 3/4 is the fraction three quarters
Decimal: 0.75 (75/100) is the decimal fraction representing three quarters
Percentage: 75% means the same as 3/4 or 0.75
Different interpretations of fractions
- To describe equal parts of a whole
- To describe equal parts of a collection of objects
- To denote numbers e.g. 1/2 is midway between 0 and 1
- As operators related to division e.g. 2/3 of the class
- To indicate division e.g. the truck is 3 times as long as the car, or in a ratio of 3:1
Fractions as a number
(number line)
A fraction refers to a number that can be located on a number line
Fractional units in combination with whole units provide an accurate means of measuring
E.g. 1/2, 7/8, 1 3/4, 5/2 (from left to right on number line)
Fractions as operators
The fraction can act as an operator related to division, that transforms a quantity by reducing (shrinking) or enlarging (stretching) the size of a quantity
E.g. 3/4 of the 16 participants at the workshop were men. How many men attended the workshop?
12
Fractions represent division
A fraction can represent the result of division between two whole numbers
E.g. sharing 12 drinks between 6 kids
12 divided by 6 = 12/6 = 2/1 = 2
Fractions represent a ratio
The fraction represents a multiplicative relationship to compare the size of 2 sets
E.g. the number of girls in the class is 2/3 the number of boys
= 2:3
2 girls for every 3 boys
If there are 6 boys in the class, how many girls are there?
3/2 (boys - girls)
4/10 (class is girls)
6/10 (class is boys
Equivalent fractions
For whole numbers, there is only one way of representing a number of numerals (0-9)
A fraction quantity, like a decimal, can be represented by an infinite number of ways
All fractions in an equivalence class are interchangeable since they represent the same quantity
E.g. 1/2 = 2/4 = 3/6 = 4/8
The equivalent fraction is achieved by multiplying or dividing the numerator and the denominator by the same number
Most common use of fractions
Calculating a simple fraction of a group of quantity
E.g. 1/3 off sale
Cost $60
1/3 of $60 = $20
60-20 = $40
Numbers with Letter Symbols
Natural
Integers
Rational
Real Numbers
Complex
Natural = N
Integers = Z
Rational = Q
Real numbers = R
Complex = C
- Rational numbers and irrational numbers form the _____
- Natural numbers {1, 2, 3, …} are a subset of _____
- Integers are a subset of ________, which are ___.
- Whole numbers are a subset of ______
- set of real numbers.
- whole numbers {0, 1, 2, 3,…}
- rational numbers, any numbers which can be expressed as a terminating or recurring decimal or fraction
- integers {…, -3, -2, -1, 0, 1, 2, 3, …}
Use of fractions
4 ways
A part of a whole (shape half shaded in = 1/2)
Fractions as a number (number line, pointed to the middle = 1/2)
Fractions as division (1 divided by 2 = 1/2)
Fractions as part of a set (1 red ball and 1 white ball, fraction of red balls is 1/2)