Addition and Subtraction of Natural and Whole Numbers
Amit is a good boy
He likes to go to school every day
And he always does his homework on time
Today he got 2 problems to solve
But, before doing his homework he always revises what he has learned in today's class
So, in today's class Amit studied about a number line
It is a straight line with numbers placed at equal intervals, and the line continues to left and right forever
The number on the right is greater than the numbers on the left. So when we add, we move to the right
And the number on the left is lesser than the numbers on the right. So when we subtract, we move to the left
Now let us help Amit solve the 2 problems based on the number line
In the first problem Susan and Joe are playing a board game
Susan rolls a 5 in a dice
She moves 5 places forward and lands on a square which tells her to move more 3 spaces forward.
Now Amit needs to find out the number of spaces Susan moved in her turn
Using the number line, when Susan didn't throw the dice the spaces moved by her was 0.
After throwing the dice, she moved 5 spaces, so moving 5 intervals on the right since we are adding
Now, after landing, the square tells to move more 3 spaces, so moving 3 more intervals on the right
So, according to the number line, Amit found that Susan moved 8 spaces during her turn
Now if instead of 5 and 3, if it would have been bigger numbers, then Amit would have used Normal addition
Now let us see the 2nd Problem
Emma bought 12 donuts from the shop
She gave 3 donuts to her sister
And 2 to her mother
Amit needs to calculate the number of donuts left with her
On the number line, when Emma bought 12 donuts, we need to move right 12 intervals as we are adding
Now, since she gave 3 donuts to her sister so Amit needs to subtract. So, he moves 3 intervals on the left
And again she gives 2 more donuts to her mother. So, Amit moves 2 more intervals on the left
So, Amit finds out that Emma has only 7 donuts left.
Now instead of these small numbers if there had been bigger numbers then Amit have to use normal subtraction
As it is impossible to plot bigger numbers on the number line on a piece of paper we do normal addition and subtraction
Amit was happy as he finished his homework and now he can go and play outside
Revision
A number line is a straight line with numbers placed at equal intervals, where the line continues left and right forever
The number on the right is greater than the numbers on the left. So when we add, we move to the right
And the number on the left is lesser than the numbers on the right. So when we subtract, we move to the left
The End