HP F2226A - 48GII Graphic Calculator User Manual page 259

Addition of a single number to a list produces a list augmented by the
number, and not an addition of the single number to each element in the list.
For example:
Subtraction, multiplication, and division of lists of numbers of the same length
produce a list of the same length with term-by-term operations. Examples:
The division L4/L3 will produce an infinity entry because one of the elements
in L3 is zero:
If the lists involved in the operation have different lengths, an error message is
produced (Error: Invalid Dimension).
The plus sign (+), when applied to lists, acts a concatenation operator,
putting together the two lists, rather than adding them term-by-term. For
example:
In order to produce term-by-term addition of two lists of the same length, we
need to use operator ADD. This operator can be loaded by using the function
catalog (‚N). The screen below shows an application of ADD to add
lists L1 and L2, term-by-term:
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