Page 256 - ICSE Math 6

NEGATIVE NUMBERS AND INTEGERS

Integers

… –5 –4 –3 –2 –1 0 1 2 3 4 5…
Negative integers Positive integers

Absolute Value Comparison of Integers
• Negative integers < 0 < Positive integers
| –x | = x • (x + positive integer) is always greater than x.
• (x + negative integer) is always less than x.
| 0 | = 0 • (y – positive integer) is always less than y.

• (y – negative integer) is always greater than y.
| +x | = x
• Absolute value of x is greater than or equal to x.

Adding and Subtracting Integers on a Number Line
Addition Subtraction

• To add (+a) to b, move a units to the • To subtract (+a) from b, move a units
right of b. to the left of b.
• To add (–a) to b, move a units to the • To subtract (–a) from b, move a units to
left of b the right of b.

PLAYING WITH NUMBERS

Factor Multiple
Definition: Definition:
A factor of a number divides the number completely without leaving A multiple of a number is obtained by multiplying
any remainder. the given number by a natural number.
Properties: Properties:
• 1 is a factor of every number. • A multiple of a number is greater than or equal
• Every number is a factor of itself. to the number.
• A factor of a number is either less than or equal to the given number. • Every number is a multiple of 1 and itself.
• Factors of a number are finite. • Multiples of a number are infinite.

Types of Numbers HCF
• Even number: A number which is divisible by 2. The HCF of two or more given numbers is the largest factor
• Odd number: A number which is not divisible which divides each of the given numbers completely.
by 2. For example, HCF of 5 and 10 is 5.
• Prime number: A number with exactly two
factors (1 and itself). LCM
• Composite number: A number with more than
two factors. The LCM of two or more numbers is the smallest common
• Co-prime numbers: Two numbers with 1 as the multiple of the given numbers.
only common factor. For example, LCM of 2 and 3 is 6.

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