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A mathematical typesetting style selects layout conventions appropriate to a formula's context, including compact inline material and more spacious displayed material. In MathML, math-style distinguishes normal and compact, while math-depth participates in nested size selection.^[ref]

Compare two presentations of the same expression:Both represent the same quotient, but reserve different vertical space. In TeX, \displaystyle and \textstyle request these contexts. The choice matters when fitting a typeset fraction into a line without making neighbouring text baselines unnecessarily far apart.

For a hypothetical computer font with first- and second-level script scales 80 and 60 percent, a base font size of 20 units gives script sizes 16 and 12. The second value is relative to the base, so it is not $0.8^2(20)=12.8$. Actual percentages come from the computer font's mathematical font constants.^[ref]

MathML is a markup language for mathematical notation, structure and content on the web. Its elements describe expressions within a document rather than reducing a formula to a flat character string. MathML Core specifies a subset suited to web browser implementation; the cited 24June2025 document is a Candidate Recommendation Snapshot.^[ref]

Consider the typeset fraction $\frac{x+1}{2}$. A presentation encoding is <math xmlns="http://www.w3.org/1998/Math/MathML"><mfrac><mrow><mi>x</mi><mo>+</mo><mn>1</mn></mrow><mn>2</mn></mfrac></math>. The mi, mo and mn elements identify a symbolic name, an operator and numbers. The mrow groups the numerator; the two children of mfrac provide the numerator and denominator.^[ref]

Grouping changes the represented expression. At $x=3$, the intended fraction gives $(3+1)/2=2$, whereas $x+1/2=7/2$. This arithmetic illustrates the meaning assigned to the structure; MathML presentation markup does not itself execute the calculation. Maintaining a structured representation helps document tools manipulate a formula and lets layout follow its mathematical grouping.

MathML Core is a browser-oriented subset of MathML with specified rules for mathematical presentation and layout. The pinned 24 June 2025 document is a Candidate Recommendation Snapshot. It defines a concrete target for implementation, rather than identifying the whole MathML language with one browser's output.^[ref]

For an original example, encode a typeset fraction surrounded by parentheses as <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo stretchy="true">(</mo><mfrac><mi>x</mi><mn>2</mn></mfrac><mo stretchy="true">)</mo></mrow></math>. The row has three children: a left mathematical delimiter, the typeset fraction and a right mathematical delimiter. The fraction's children supply numerator $x$ and denominator 2.

The parentheses are stretchy mathematical operators: their markup requests size-sensitive layout around the fraction. Core specifies operator stretching and row layout; mathematical glyph variants or mathematical glyph assemblies can supply suitable forms.^[ref] This illustrates why presenting a formula requires more than placing all its characters on one text baseline.

Changing stretchy="true" to stretchy="false" changes the layout instruction without changing the fraction's two operands. Exact dimensions also depend on the computer font and applicable layout properties. The markup supplies structure and presentation instructions; substituting a numerical value for $x$ and evaluating the quotient is a separate operation.

A subscript is a component placed below the usual baseline of a base expression, commonly at a smaller size. It can label a term of a sequence, as in $x_i$, or identify a matrix entry, as in $a_{ij}$. Its position does not by itself determine the mathematical meaning of the label.

In TeX, x_i attaches a single-token subscript, while x_{i+1} groups a compound subscript. In MathML, msub supplies a base and subscript as separate children. Their layout uses baseline shifts and clearances rather than putting both components on the ordinary text baseline.^[ref]

For example, $x_{i+1}$ keeps $i+1$ together as one attached component. A mathematical typesetting style controls the treatment of the smaller expression. An OpenType MATH table can supply the font-specific placement data. This is why adding an underscore as an ordinary printed glyph would not reproduce the layout.

A superscript is a component raised relative to a base expression, commonly also reduced in size. An exponent in $x^2$ is one use. The superscript in $f^{(k)}(x)$ can instead denote a derivative when that convention has been specified. The typographic position supports several meanings.

In TeX, x^2 supplies one token as the superscript and x^{n+1} groups a longer expression. In MathML, msup lays out the base and superscript separately, with vertical placement and gap constraints.^[ref]

For example, the base and raised expression inhave different local baselines. A mathematical typesetting style determines how the raised expression is presented. When subscripts and superscripts are both attached, their mutual clearance also matters; independently moving each one without considering the other could cause a collision. An OpenType MATH table provides font-specific data used for these choices.

A typeset fraction is a two-dimensional layout that places one expression above another, commonly with a horizontal rule between them. The components are laid out as typesetting boxes before they are assembled. In MathML, an mfrac element supplies the two components; mathematical typesetting style affects their presentation.^[ref]

For example,has a superscript in its upper component and a square root in its lower component. Their dimensions influence the space above and below the fraction rule. The expression's algebraic meaning and its geometry are related but distinct: the layout can contain arbitrary expressions, including ones whose values are not rational numbers.

A simple own box model makes the horizontal placement explicit. Suppose the component widths are $w_1=18$ and $w_2=10$, and the layout adds a chosen side allowance $p=2$. If both components are centred in widththeir left offsets are $(22-18)/2=2$ and $(22-10)/2=6$. This is an illustrative centring model; real layouts also use vertical clearances, rule thickness and font data from an OpenType MATH table.