Reference :
MDN Number
MDN Math

Conversions from String

Number("123");       // 123
Number("12.3");      // 12.3
Number("12.00");     // 12
Number("123e-1");    // 12.3
Number("");          // 0
Number("0x11");      // 17
Number("0b11");      // 3
Number("0o11");      // 9
Number("toto");      // NaN
Number("100a");      // NaN
Number("-Infinity";) // -Infinity

parseInt("10");         // returns 10
parseInt("10.33");      // returns 10
parseInt("10 20 30");   // returns 10
parseInt("10 years");   // returns 10
parseInt("years 10");   // returns NaN 

parseFloat("10");        // returns 10
parseFloat("10.33");     // returns 10.33
parseFloat("10 20 30");  // returns 10
parseFloat("10 years");  // returns 10
parseFloat("years 10");  // returns NaN

Precision of number

var x = 9.656;
x.toPrecision();        // returns 9.656
x.toPrecision(2);       // returns 9.7
x.toPrecision(4);       // returns 9.656
x.toPrecision(6);       // returns 9.65600

Mathematical operations

NaN is a JavaScript reserved word indicating that a number is not a legal number.

Trying to do arithmetic with a non-numeric string will result in NaN (Not a Number):

var x = 100 / "Apple";  // x will be NaN (Not a Number)

Operations

1+2 // 3 
1-2 // -1
2*3 // 6
4/2 // 2
Math.pow(2,4) // 2^4 = 16
Math.sqrt(16) // 4 
Math.exp(x) // e^x

Trigonometry

Math.cos(x)
Math.sin(x)

Min, max

x = [1,2,3,4,5]
Math.min(x) // 1
Math.max(x) // 5 

Calculate the average for 6 numbers (for javascript multiple, without using GroupByColumn)

const elmt = [1,2,3,5,4,48,6,52]

var sum = 0;
for( var i = 0; i < elmt.length; i++ ){
    sum += elmt[i]
}

var avg = sum/elmt.length; 
// avg = 15.12

Averaging values contained in variables separated by

Ex: _str1 contains :
"#199.67#199.67#199.67#199.65#199.65#199.65#199.65#199.65#199.65#199.65#199.65#199.65#199.61"

javascript.util.StringTokenizer st = new javascript.util.StringTokenizer(_str1,"#");
double d=0;
int nCount=0;
while (st.hasMoreTokens())
{
    String str=st.nextToken();
    d+=Str.ToDouble(str);
    nCount++;
}

if (nCount==0)
  return "";
else
  return d / nCount;