In mathematics, there are two modes of displaying expressions, namely an inline mode and a displayed mode.

• An inline equation refers to an equation that is within a line of text. An equation is placed inline if it is short and involves small symbols.

• A displayed equation refers to an equation which is displayed on its own lines.  Displayed equations are used when we need to label them or when they are hard to read if placed inline or when we want attention from the readers. A displayed equation should be centred, and any punctuation at the end should be inside the mathematical environment (that is, the punctuation should be next to the displayed expression, not on the next line).

• When you align several equations, it is advised that these equations should be centred and aligned along the relations and etc.

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