For users of Maple 2018 and earlier versions: This error message is displayed when the assignment cannot be made because the number of elements on both sides are not the same.

The assignment operator (:=) assigns the value of the right-hand side to the left-hand side, where the left-hand side must be a name, indexed name, function call, or sequence of these, and the right-hand side is an expression or sequence of expressions. Assigning a sequence of names on the left-hand side of the assignment operator to a sequence of values on the right-hand side is known as multiple assignment. If the left-hand side is a sequence of names, the right-hand side must evaluate to a sequence of expressions with the same number of members as the left-hand side.

The cannot split rhs for multiple assignment error occurs when the number of members in the expression sequence on the right-hand side (rhs) is less than the number of members in the sequence of names on the left-hand side.

Trying to assign the value 5 to $x$and $y$

Solution:

In any multiple assignment, the number of elements on the left-hand side must equal the number of elements on the right-hand side or else Maple will not know how to proceed with the assignment.