1. Mathcad Basics
The Mathcad does not require any programming language to perform simple operations.
The Mathcad follow the precedence of operation such as division, multiply, addition, and subtraction.
The Mathcad displays the equations form as it is written on the paper.
Any time you edit a previous part of the document, Mathcad will automatically re-evaluate the rest of the worksheet.
if the answer does not appear, look under the Math menu and make sure Automatic Calculation is selected

2. Firstly, we begin with some simple math
Firstly, we begin with some simple math. In worksheet, you begin at the mouse cursor to enter the variables, numbers or any expression...etc.
Let’s begin with some simple math. Write 5+3=
You get
Or type (2+3)*2= You should get the following:
You notice get the result after press (=) directly.
Another example, print / = you get
Another way to create a simple expression is to type an operator such as +, -, *, or / this will create empty placeholders (black boxes) that you can then click to fill in the numbers or operands.

3. Variables and functions
The variable must be defined above or to the left of where it is being used.(note: the variables should be defined before the functions)
To assign a value to a variable, type the variable name and then type the colon : key.
  For example, type a1:5+3
After that type a1= this evaluates and displays the value of variable a1.
Another variable, type b1:=10. Now that values are assigned to variable a1 and variable b1, you can use these variables in equations.
Type c1:a1+b1
When you type c1=. You should get the following result .

4. You should note the Mathcad followed the precedence rule, for example “15-6/3=” the division (6/3) before the subtraction (15-6) when evaluating this expression. This is because Mathcad always follows a hierarchy of operator evaluation; powers are performed first, followed by multiplication and division, followed by addition and subtraction.
You can force Mathcad to carry out the subtraction first by placing parentheses around the subtraction.

6. Equal Signs
There are different forms of equal signs used in Mathcad. It is important to understand the difference between them.
The assignment operator (:=) COLON is used to define variables, functions, or expressions.
The evaluation operator (=) EQUAL SIGN is used to evaluate a variable, function, or expression numerically.
The Boolean equality operator CTRL+EQUAL SIGN is used to evaluate the equality condition in a Boolean statement. It is also used for programming, solving, and in symbolic equations. You can find it on Boolean toolbar.