Basics of Number System

The notation of set of natural numbers is denoted by $Z$.

The notation of set of natural numbers is denoted by $W$.

The notation of set of natural numbers is denoted by 

How do you write a set of natural numbers?

The notation of set of whole numbers is denoted by $N$.

The notation of set of whole numbers is denoted by $Z$.

The notation of set of whole numbers is denoted by 

How do you write a set of whole numbers?

The notation of set of integers is denoted by $N$.

The set of integers of integers are denoted by

How do you write a set of integers?

Product of two numbers is $\frac{-20}{9}$. If one of them is $4$, then the other is

$0.090909.....$is equal to

Express $\frac{5}{48}$ in decimal form.

Simplify: $3\frac{1}{4}-\left(7\frac{3}{4}-1\frac{1}{2}\right)÷1\frac{1}{4}$

Write whether the following statement is true or false. Give reasons:

Every natural number is a whole number.

Express $3.05$ as a fraction in simplest form.

Find the value of $x: x^2=7744$.

Find the value of $x: x^2=2304$.

Find the value of $x: x^2=225$.