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(dc.info)Arithmetic

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Arithmetic
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`+'
     Pops two values off the stack, adds them, and pushes the result.
     The precision of the result is determined only by the values of
     the arguments, and is enough to be exact.

`-'
     Pops two values, subtracts the first one popped from the second
     one popped, and pushes the result.

`*'
     Pops two values, multiplies them, and pushes the result.  The
     number of fraction digits in the result is the largest of the
     precision value, the number of fraction digits in the multiplier,
     or the number of fraction digits in the multiplicand; but in no
     event exceeding the number of digits required for an exact result.

`/'
     Pops two values, divides the second one popped from the first one
     popped, and pushes the result.  The number of fraction digits is
     specified by the precision value.

`%'
     Pops two values, computes the remainder of the division that the
     `/' command would do, and pushes that.  The value computed is the
     same as that computed by the sequence `Sd dld/ Ld*-' .

`~'
     Pops two values, divides the second one popped from the first one
     popped.  The quotient is pushed first, and the remainder is pushed
     next.  The number of fraction digits used in the division is
     specified by the precision value.  (The sequence `SdSn lnld/
     LnLd%' could also accomplish this function, with slightly
     different error checking.)  (This command is a GNU extension.)

`^'
     Pops two values and exponentiates, using the first value popped as
     the exponent and the second popped as the base.  The fraction part
     of the exponent is ignored.  The precision value specifies the
     number of fraction digits in the result.

`|'
     Pops three values and computes a modular exponentiation.  The
     first value popped is used as the reduction modulus; this value
     must be a non-zero number, and the result may not be accurate if
     the modulus is not an integer.  The second popped is used as the
     exponent; this value must be a non-negative number, and any
     fractional part of this exponent will be ignored.  The third value
     popped is the base which gets exponentiated, which should be an
     integer.  For small integers this is like the sequence `Sm^Lm%',
     but, unlike `^', this command will work with arbritrarily large
     exponents.  (This command is a GNU extension.)

`v'
     Pops one value, computes its square root, and pushes that.  The
     precision value specifies the number of fraction digits in the
     result.

   Most arithmetic operations are affected by the _precision value_,
which you can set with the `k' command.  The default precision value is
zero, which means that all arithmetic except for addition and
subtraction produces integer results.