MathML Basic Elements

The most basic elements of MathML are: mrow, mi, mo and mn.

Index	Elements	Descriptions
1)	<mrow> element	The MathML <mrow> element is used to group any number of sub expressions horizontally.
2)	<mi> element	The MathML <mi> element is used to specify an identifier.
3)	<mo> element	The MathML <mo> element is used to specify an operator in a broad sense.
4)	<mn> element	The MathML <mn> element is used to specify a numeric literal.

For example: To write x + y = 5, the equivalent MathML code are:

1. <mrow>  
2.   <mrow>  
3.     <mi>x</mi>  
4.     <mo>+</mo>  
5.     <mi>y</mi>  
6.   </mrow>  
7.   <mo>=</mo>  
8.   <mn>2</mn>  
9. </mrow>  

<mrow> element:

The MathML <mrow> element is used to group any number of sub expressions horizontally.

<mi> element:

The MathML <mi> element is used to specify an identifier. For example: the name of a variable, a constant, a function, etc.

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It automatically renders the identifier using an italic font, if the identifier is one character long; otherwise the name is rendered using a normal, upright font.

<mo> element:

The MathML <mo> element is used to specify an operator in a broad sense. For example: addition operator ‘+’, a fence operator ‘{‘ or a separator ‘,’

The appropriate amount of space is added on the left and on the right of an <mo> element depending on the textual contents of this element.

For example: if in the above expression you replace <mo>+</mo> by <mo>,</mo>, this will suppress the space at the left of the mo element.

<mn> element:

The MathML <mn> element is used to specify a numeric literal.

For example: PI should be specified as <mi>PI</mi> and not as <mn>PI</mn> while 3.14 should be specified as <mn>3.14</mn> and not as <mi>3.14</mi>.