Square brackets are always used in pairs.
Sometimes, square brackets are used as a symbol to group operations, like this:
8 + 5[4 + 3(8 – 4) – 2 (9 – 8) + 6] – 12 = 96
Notation
The square bracket symbol is "[ ]".
Examples
The interval [3, 8] indicates "{x ∈ [latex]\mathbb{R}[/latex] ∣ 3 ≤ x ≤ 8}".
The interval [3, 8[ indicates "{x ∈ [latex]\mathbb{R}[/latex] ∣ 3 ≤ x < 8}".
The interval ]3, 8] indicates "{x ∈ [latex]\mathbb{R}[/latex] ∣ 3 < x ≤ 8}".
The interval ]3, 8[ indicates "{x ∈ [latex]\mathbb{R}[/latex] ∣ 3 < x < 8}".
Examples
The first person to use square brackets was
Raphael Bombelli (1526-1573) in his text called
Algebra. He was one of the great Italian algebrists of the 16th century. He used the four base operations with complex numbers and used continuous fractions to calculate square roots and cube roots.
