# what does the word [n] mean in math

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Hello!

For real number `x,` the symbol `[x]` means the integer part of `x,` i.e. the largest integer number not greater than `x.`

In decimal notation for positive `x=n.mkl...,`

`[x]=n.`

For example, `[2.1]=2.`

For negative `x=-n.mkl...`

`[x]=-n-1` if some numbers `m, k, l, ...` aren't zero.

For example, `[-2.1]=-3.`

For any integer `x` `[x]=x.`

Sometimes this function is called *floor function* and is denoted `|__x__|.`

The *ceiling function* is defined as the smallest integer not less than `x` and is denoted `|~x~|.`