# ActionScript 3Working with numerical values

## Whether a number is an even value

``````function isEven(n:Number):Boolean {
return ((n & 1) == 0);
}
``````

Examples:

``````isEven(1); // false
isEven(2); // true

isEven(1.1); // false
isEven(1.2); // false
isEven(2.1); // true
isEven(2.2); // true
``````

## Whether a number is an odd value

``````function isOdd(n:Number):Boolean {
return ((n & 1) == 1);
}
``````

Examples:

``````isOdd(1); // true
isOdd(2); // false

isOdd(1.1); // true
isOdd(1.2); // true
isOdd(2.1); // false
isOdd(2.2); // false
``````

## Rounding to nearest X

To round a value to the nearest multiple of x:

``````function roundTo(value:Number, to:Number):Number {
return Math.round(value / to) * to;
}
``````

Example:

``````roundTo(8, 5); // 10
roundTo(17, 3); // 18
``````

## Roundoff errors of floating point numbers

``````/**
* @param n Number to be rounded.
* @param precision Decimal places.
* @return Rounded Number
*/
function roundDecimal(n:Number, precision:Number):Number {
var factor:int = Math.pow(10, precision);
return (Math.round(n * factor) / factor);
}
``````

Examples:

``````trace(0.9 - 1); // -0.09999999999999998

trace(roundDecimal(0.9 - 1, 1));     // -0.1
trace(roundDecimal(0.9 - 1, 2));     // -0.1

trace(roundDecimal(0.9 - 1.123, 1)); // -0.2
trace(roundDecimal(0.9 - 1.123, 2)); // -0.22
trace(roundDecimal(0.9 - 1.123, 3)); // -0.223
``````

## Displaying numbers with required precision

``````var a:Number=0.123456789;
trace(a);                    // 0.123456789
trace(a.toPrecision(4));     // 0.1235
trace(a.toFixed(4));         // 0.1235
trace(a.toExponential(4));   // 1.2345e-1
trace(a.toString(16));       // 0 - works for integer part only
var b:Number=12345678.9876543; // a bigger number to display rounding
trace(b);                    // 12345678.9876543
trace(b.toPrecision(4));     // 1.235e+7
trace(b.toFixed(4));         // 12345678.9877
trace(b.toExponential(4));   // 1.2345e+7
trace(b.toString(16));       // bc614e
b=1.0e+16;
trace(b.toString(36));       // 2qgpckvng1s
``````