Why should you never use '=sum(A1+A2)'?

[Ted Rogers]

I attended an Excel training course yesterday and looking through the
handout this morning noticed these lines in the overview:

'.......when to use '=A1+A2' and when to use '=sum(A1:A10)' and why you
should never use '=sum(A1+A2)'. I can't for the life of me remember the
trainer's explanation and can't find the answer anywhere. Could anyone help
please?

Ted

 

[JE McGimpsey]

The SUM() function is superfluous in this case. Example:

A1: 5
A2: 6
A3: =A1 + A2 ====> 11
A4: =SUM(A1 + A2) ===> SUM(11) ====> 11

 

[Bob Phillips]

Because you are effectively trying to do the same command twice

A1+A2 is summing those two cells,
SUM is also saying to sum them

You get the correct answer because the A1+A2 is resolved before the SUM acts
upon it, but it is unnecessary, and will be inefficient in a large
spreadsheet.

 

[Dave Peterson]

=sum() ignores cells with text in them:

A1: ASDF
A2: 3

=sum(a1:a2) will return 3
=sum(a1+a2) will return a #value! error
(because a1+a2 will return a #value! error)

 

[Ted Rogers]

=sum() ignores cells with text in them:

A1: ASDF
A2: 3

=sum(a1:a2) will return 3
=sum(a1+a2) will return a #value! error
(because a1+a2 will return a #value! error)

Many thanks to everyone for your kind help - I appreciate it.

Ted