### 4.13.2 number expressions

A number expression is:

1. a rational number (there are NO spaces allowed inside a rational number, see int expressions)
2. a floating point number (if the coefficient field is `real`):
   <digits>`.`<digits>`e`<sign><digits>
3. an identifier of type number
4. a function returning number
5. an int expression (see Type conversion and casting)
6. number expressions combined by the arithmetic operations `+`, `-`, `*`, `/`, `^`, or `**`.
7. a type cast to number

Example:

      // the following expressions are in any ring int expressions
      2 / 3;
    ==> // ** int division with `/`: use `div` instead in line >>  2 / 3;<<
    ==> 0
      4/ 8;
    ==> // ** int division with `/`: use `div` instead in line >>  4/ 8;<<
    ==> 0
      2 /2;   // the notation of / for div might change in the future
    ==> // ** int division with `/`: use `div` instead in line >>  2 /2;   // the\
        notation of / for div might change in the future<<
    ==> 1
      ring r0=0,x,dp;
      2/3, 4/8, 2/2 ; // are numbers
    ==> 2/3 1/2 1

      poly f = 2x2 +1;
      leadcoef(f);
    ==> 2
      typeof(_);
    ==> number
      ring rr =real,x,dp;
      1.7e-2; 1.7e+2; // are valid (but  1.7e2 not), if the field is `real`
    ==> (1.700e-02)
    ==> (1.700e+02)
      ring rp = (31,t),x,dp;
      2/3, 4/8, 2/2 ; // are numbers
    ==> 11 -15 1
      poly g = (3t2 +1)*x2 +1;
      leadcoef(g);
    ==> (3t2+1)
      typeof(_);
    ==> number
      par(1);
    ==> (t)
      typeof(_);
    ==> number

See Type conversion and casting; ring.

User manual for Singular version 4-0-3, 2016, generated by texi2html.