Category : 5th Class
LEARNING OBJECTIVE
This lesson will help you to:—
Real - Life Examples
Example: Pizza can be divide into 8 pieces so that all the four friends can eat two slices of pizza each.
3-(-2) = 3 + 2 = 5
QUICK CONCEPT REVIEW
What are operations?
An operation is an action or procedure which produces a new value from one or more input values, called "operands".
Operations such as addition, subtraction, multiplication and division are binary operations since they involve two or more values.
The Basic Operations
Symbol |
Words Used |
+ |
Addition, Add, Sum, Plus, Increase, Total |
- |
Subtraction, Subtract, Minus, Less, Difference, Decrease, Take Away, Deduct |
\[\times \] |
Multiplication, Multiply, Product, By, Times, Lots of |
\[\div \] |
Division, Divide, Quotient, Goes Into, How Many Times |
Historical preview
ADDITION
Properties for Addition
a + b = b + a
a + (b + c) = (a + b) + c
a + 0 = a
SUBTRACTION
Subtraction is taking one number away from another.
Minuend: The number that is to be subtracted from.
Subtrahend: The number that is to be subtracted.
Difference: The result of subtracting one number from another.
MULTIPLICATION
Multiplication in its simplest form is repeated addition.
Misconcept / Concept
Misconcept: Dividing a number by 0 gives 0. Example: 3/0=0
Concept: We know that 0/3=0.
Conveniently. We also assume the same result for 3/0. This is not true as 3/0 is undefined.
Misconcept: Zero divided by zero is equal to 1. i.e. 0/0 = 1.
Concept: We all are aware that 3/3, 5/5, -10/-10 result in 1. As long as we see fraction in the form of a/a, we will expect an answer of 1. This however does not hold when a = 0 as 0/0 is undefined.
Here we see that 6+6+6 (three 6s) make 18.
It could also be said that 3+3+3+3+3+3 (six 3s) make 18.
But you can also multiply by fractions or decimals, which goes beyond the simple idea of repeated addition:
Example: 3.5 x 5 = 17.5 which is 3.5 lots of 5, or 5 lots of 3.5
Properties for Multiplication
a x b= b x a
a x (b x c) = (a x b) x c
a x 1 = a
a x 0 = 0
DIVISION
\[12\div 3=4\]
12/3=4
DIVIDEND - DIVISOR = QUOTIENT
12 is the dividend, 3 is the divisor, 4 is the quotient.
ORDER OF OPERATIONS
B Brackets first
O Orders (i.e. Powers and Square
Roots, etc.)
DM Division and Multiplication (left-
to- right)
AS Addition and Subtraction (left-to-
right)
PLACE VALUE
OPERATIONS OF FRACTIONS AND DECLMAL NUMBERS
The fractional and decimal numbers are operated the same way as whole numbers.
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