# Grouping

Many grouping symbols are typed in Nemeth using matching opening and closing symbols. The most common are parentheses (dots 12356 and dots 23456), brackets (dot 4 dots 12356 and dot 4 dots 23456), and braces (dots 46 dots 12356 and dots 46 dots 23456).

When you type the opening symbol of any grouping symbol, the equation editor will supply the matching closing symbol, and provide you a place to enter the expression enclosed between the opening and closing symbol.

At any point, if you type the matching closing symbol, the equation editor input will move outside the grouping symbols to allow you to type additional input after the closing symbol. The braille display will indicate the change of input position by underlining the entire group with dot 8.

The absolute value symbol (dots 1256) is special in that the same symbol is used for the opening and closing of an absolute value expression. The equation editor treats the first dots 1256 as an opening absolute value, and any subsequent dots 1256 as the matching closing absolute value symbol. Because of this, the "norm" symbol, which is shown as two vertical bars, cannot be typed in the equation editor at present.

## Exercises

Type the following expressions into the equation editor below and verify that the equation editor produces the proper Nemeth braille output in each case. Also verify that a sighted friend can read each expression you have typed as it is displayed on the screen. Feel free to try your own examples, and to explore other less common grouping symbols.

• 2 * ( 3 + 4 )
• [ 5 - 2 ] / 3
• ( x - 1 ) * ( x + 1 )
• 2 + { 3 - [ 4 * ( 5 / 6 ) ] }
• | x + y | <= | x | + | y |