Addition with multiple criteria within the same column

Happy retirement to you too.
Maybe next time. I'm discovering EXCEL step by step. This tool has evolved a lot since the version I used 20 years ago!
I'm having fun ... It allowed me to see through graphs that despite a decrease in my EDF consumption in 2011, my bill has indeed increased!
A retiree

Thank you so much, Vaucluse! What a quick response!
The first formula:
=SUMIF(B4:B42,"Leroy Merlin",E4:E42)¨SUMIF(B4:B42,"Castorama",E4:E42)
Excel does not accept the second SUMIF preceded by the diaeresis ...?

The second formula worked:
=SUMPRODUCT(((B4:B42="Leroy Merlin")+(B4:B42="Castorama"))*(E4:E42))
In my mind, this formula containing "PRODUCT" + the exponential "*" was supposed to correspond to multiplication, so I didn't try to make an addition.
Thanks again.

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A retiree

Thank you too, ccm81. I tried:
=SUMIF(B4:B42,"Leroy Merlin",E4:E42)+SUMIF(B4:B42,"Castorama",E4:E42)
So, by replacing the umlaut with the + sign, I get the following error message:
Sorry ...
When the first character is = or - , Excel considers it a formula:
You type: =1+1, the cell displays: 2
You type: '=1+1, the cell displays =1+1
With SUMIF twice I can't manage.
If you find a solution, let me know ... Thank you.
A retiree

I'm surprised by your rather harsh response towards me.
I thanked you for your promptness, stating that while the first formula did not work, the second one, on the other hand, worked perfectly.
To explain to you that I had not used this function by myself before having your help, I told you that "PROD" meant "multiply" to me even though it was attached to SUM.
However, that doesn't mean I neglected the SUM.
You ask me for the error message even though I copied it (Hard Copy impossible / Copy-paste of text impossible. Here it is again:
"When the first character is a sign = or - , excel considers it a formula:
You type: =1+1, the cell displays: 2
You type: '=1+1, the cell displays =1+1"
You ask me for the formulas even though I copied them (by copy/paste). Here they are again:
=SUMPRODUCT(((B4:B42="Leroy Merlin")+(B4:B42="Castorama"))*(E4:E42))
and
=SUMIF(B4:B42;"Leroy Merlin";E4:E42)+SUMIF(B4:B42;"Castorama";E4:E42)
You tell me: "Then why not try it, since it's the simplest... and since you're being advised??"
I tried it as soon as I received it, it worked and I thanked you immediately. So I do not understand.
Thank you again.
A retiree

Hello,
By the way, for the "$", a quick visit to here!

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Regards.
The Penguin

Thank you very much, Pingou. This will help me. I didn't know this and had to correct my formulas after each copy!
A retiree

Thank you and enjoy your retirement just like I will.

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Best regards.
The Penguin