Integer is any number in the number line which is a whole number not including fraction. It includes 1, 2, 3,… and their opposite signs, -1,-2,-3,… including 0. Integers are signed numbers, negative(-1) and positive (+). When a number; say 2 is given, it is written as +2 or 2, without a sign is considered as positive. A negative number say negative 2 is written as -2.
In other words, the positive integers are the counting numbers,: 1,2,3,… on the right of 0 or at the x –axis in the coordinate system, whereas, the negative integers are those numbers opposite sign. Going to the right of the x-y axes coordinate system indicates positive, going to the left indicates negative. Going up of at the y coordinate indicates positive, and going down of the coordinate axis indicates negative sign.
The x-y Coordinate system
Integers in reality
|Adding how many||Deducting points|
|Deposit money in bank||Withdrawing money from bank|
|Earning money from somewhere||Borrowing money from anywhere|
|Winning at any case||Losing at any case|
|Increasing or Incrementing||Decreasing or devaluating|
|Going to the east||Going to the west|
|Going up an elevator||Going down at an elevator|
|Swimming up from the ocean||Diving into the ocean|
|Airplane flying up in the sky||Submarine sailing in the deep ocean|
|Rising of temperature at any time||Freezing of temperature at any time|
|Standing taller||Bowing down to sit down|
Operations in Integers: Addition and Subtraction
- – 4 + 11 = 7
- – 4 + (+11) = 7
- 4+11= 15
- +4 + (+11) = 15
- -20 + 6 = -14
- – 50+-13 = – 63
- -1+ – 99 = – 100
- 1+99 = 100
- 37 + -2 = 35
- -2 + – 3 = – 5
Important Rule to Use:
Adapt the lyrics from the song tune of the song: Row, row your boat:
Same sign, add and keep,
Different sign, subtract
Take the sign of the bigger number
Then you will be exact
Click on the link below to play:
1. Mr. Mishra deposited 10,000 dollars and withdrew 2000 dollars a week after. How much money remained to his bank account?
Solution: $10000 + ( – 2000) = $8,000 or
$10000 – 2000 = $8,000 remaining amount
2. Pao dives 2 meters down the ocean from a view deck of 5 meters above sea level, then swam a bit level up of a meter. How deep is his current position from the sea level?
Solution: -2 + 5 + 1 = 4 or
5 +(-2) + (1) = 4m
3. Susie borrowed 1 baht today and borrowed 9 baht a day after from her friend. How much money Susie owed in total?
Solution: -1 + -9 = -10 (follow subtraction rule)
4. Susie owed 10 baht from friend and returned 5 baht today, how much does she still owe her friend?
Solution: -10 – (+) 5 = – 5
+ – if the operation is subtraction,
change the subtraction sign to addition
and change sign of the subtrahend, then proceed to addition rule
Have a nice day!