# Whole Number

Collection of natural numbers along with 0 is called the set of whole numbers.

e.g. 0,1,2,3,...

Whole numbers consist of positive integers and 0 which is neither positive nor negative.

The number system we use is a 'base 10' system. Therefore, each 'column' in the place value system is a power of 10 as shown below.

## • Rounding Whole Numbers

To round to the nearest ten means to find the closest number having all zeros to the right of the tens place. Note: when the digit 5, 6, 7, 8, or 9 appears in the ones place, round up; when the digit 0, 1, 2, 3, or 4 appears in the ones place, round down.

## • Whole Number Operations

there are Four Operations : Addition, Subtration, Multiplication and Division.

- switching the order of two numbers being added does not change the result.

45 + 65 = 110

65 + 45 = 110

- Work from right to left when two or more numbers are being added.

- The order that numbers are grouped in does not affect the result.

(4 + 76) + 3 = 76 + (4 + 3) = 83

- Adding 0 to a number leaves it unchanged.

97+0=97

### * Subtraction

- switching the order of two numbers being Subtracted changes the result

87 - 24 = 63

24 - 87 = - 63

- Work from right to left when numbers are subtracted.

### * Multiplication

- switching the order of two numbers being multiplied does not change the result.

60 X 10 = 10 X 60 = 600

- The order that numbers are grouped in does not affect the result.

8 x (7 x 12) = 12 x (8 x 7) = 672

Multiplying any number by 0 gives 0.

47 x 0 = 0

0 x 47 = 0

- Work from right to left when numbers are Multiplied.

- 1 is the multiplicative identity. Multiplying any number by 1 leaves the number unchanged.

33 X 1 = 33

1 x 33 = 33

### * Division

- switching the order of two numbers being divided changes the result.

60 ÷ 10 = 6

10 ÷ 60 = 0.106

Dividing any number by 0 gives 0.

87 ÷ 0 = 0

Work from left to right when numbers are Divided

Divide any number by 1 leaves the number unchanged.

59 ÷ 1 = 59

## • Order of Operation

Perform operations within Brackets first

Multiplication and division, whichever come first from left to right

Addition and subtraction, Whichever comes first from left to right.

76 - 25 + (25 ÷ 5) x 7

= 76 - 25 + 5 x 7

= 76 - 25 + 35

= 76 - 60

= 16

## • Factors

When a number is divided by its factors, there will be no remainder.

## • Multiples

The product of two numbers is a multiple of both numbers.