 # Daniel I. Scully

## A Beginner's Guide to MathML

### Sub-scripts & Super-scripts

Sub/Super-scripts are used in MathML not just for powers or indices, they are also used for limits.

#### Sub-scripts

Sub-Scripts are denoted with the <msub> tag. It accepts exactly 2 child elements, the first is the 'base', the second is the sub-script.

1. <msub> 
2.  <mi>x</mi> 
3.  <mi>i</mi> 
4. </msub>
${x}_{i}$

As usual, you can use grouping elements, such as <mrow>, to group multiple tags so that there are only two child elements within the <msub>.

#### Super-scripts

The <msup> behaves in exactly the same way as for sub-scripts.

1. <msup> 
2.  <mi>e</mi> 
3.  <mrow> 
4.  <mi>x</mi> 
5.  <mo>+</mo> 
6.  <mn>2</mn> 
7.  </mrow> 
8. </msup>
${e}^{x+2}$

#### Sub-script Super-script pair

For the frequently encountered case when you need both sub and super-scripts we can use the <msubsup> tag:

1. <msubsup> 
2.  <mi>x</mi> 
3.  <mi>2</mi> 
4.  <mn>i</mn> 
5. </msubsup>
${x}_{2}^{i}$

Note that this is different to nesting sub/super scripts:

1. <msup> 
2.  <msub> 
3.  <mi>x</mi> 
4.  <mn>i</mn> 
5.  </msub> 
6.  <mn>2</mn> 
7. </msup>
${{x}_{i}}^{2}$

#### Integration

1. <msubsup> 
2.  <mo>&Integral;</mo> 
3.  <mn>0</mn> 
4.  <mn>1</mn> 
5. </msubsup> 
6. <mi>x</mi> 
7. <mrow> 
8.  <mo>&DifferentialD;</mo> 
9.  <mi>x</mi> 
10. </mrow>
${\int }_{0}^{1}xdx$

#### Under and Over Scripts

Exaclty like the sub and super scripts, we can place things above and below using three similar tags: <munder>, <mover> and <munderover>

1. <munder> 
2.  <mi>x</mi> 
3.  <mo>⏟</mo> 
4. </munder> 
5. <mo>+</mo> 
6. <mover> 
7.  <mi>y</mi> 
8.  <mo>^</mo> 
9. </mover>
$\underset{⏟}{x}+\stackrel{^}{y}$
1. <munderover> 
2.  <mi>&Sum;</mi> 
3.  <mrow> 
4.  <mi>x</mi> 
5.  <mo>=</mo> 
6.  <mn>0</mn> 
7.  </mrow> 
8.  <mi>n</mi> 
9. </munderover> 
10. <mrow> 
11.  <mn>2</mn> <mi>x</mi> 
12.  <mo>+</mo> 
13.  <mn>1</mn> 
14. </mrow>
$\sum _{x=0}^{n}2x+1$

As you can see from this second example, this is a suitable way to write summations.