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