### Theory:

Patterns in whole number:
Whole number follows a unique pattern similar to the natural numbers.

We can arrange the whole numbers in the elementary shapes of line, rectangle, triangle and squares.

We form each shapes using the dots, which denotes the numbers.
Example:
Line:

Using two dots, we can make a line .

Using three dots, we can make a line as well as a triangle and .

Rectangle:

Using the number $$6$$, we can make a rectangle with $$2$$ rows and $$3$$ columns. Similarly, we can make this kind of patterns with whole numbers.

Simplified form:

To simplify the expression which consists of whole numbers; if we identify which pattern the whole numbers are formed, we can easily simplify it.
To add $100+11$, first, we should know the pattern, that $100+11$ $$=$$ $100+\left(10+1\right)$. Now we can easily simplify it.

We now apply the same method for $800+506$.

$$=$$ $$800$$$$+$$$$(500+6)$$

$$=$$ $$1300+6$$

$$=$$ $$1306$$.
Subtraction:
We can apply the same concept for subtraction.
Example:
i) Subtract: $60-9$.

That is, $$60-(9)$$ $$=$$ $$60-10+1$$ $$=$$ $$50+1$$ $$=$$ $$59$$.

ii)Subtract: $987-99$.

$$987-(99)$$ $$=$$ $$987-100+1$$ $$=$$ $$887+1$$ $$=$$ $$888$$.
Multiplication:
Even in a multiplication operation, we can use this method to simplify the complicated expressions.

Let's see how we can do it.
Example:
Simplify: $98×9$.

$\begin{array}{l}98×9=98\phantom{\rule{0.147em}{0ex}}\left(10-1\right)\\ \\ =\left(98×10\right)-\left(98×1\right)\\ \\ =980-98\\ \\ =882\end{array}$
Division:
Even in a division operation, we can use this method to simplify the complicated expressions.

Let's see how we can do it.
Example:
Simplify: $95×5$.

$\begin{array}{l}95×5=95×\frac{10}{2}\\ =\frac{950}{2}\\ \\ =475\end{array}$