For users of  Maple 15 and earlier versions: This error occurs when one or both of the operands that form the$\*$type arithmetic expression are of a type that is not allowed to be multiplied.

Example 1
In the following example, one of the operands in the arithmetic expression is a string, for arithmetic operations are not allowed.

Solution:

Changing the string, $''a''$to the variable $a$, corrects this error.

Example 2

In the following example, a space between $\mathrm{print}$and the left parenthesis implies multiplication between the two, which causes an error.

Solution:

Removing the space between $\mathrm{print}$and the left parenthesis corrects this error.

arithmetic, binary infix operators in Maple, type