HI everyone

I am trying to sum numbers of a specific day of the week like:

sumif(a1:a10;"Monday";b1:b10)

a1:a10 contains date jj/mm/yy like 01/01/2006
b1:b10 contains numbers

I did tried to convert the range a1:a10 into weekdays but this did not
work:

sumif(text(a1:a10;"dddd");"monday";b1:b10)

Can you help me with this formula

Many thanks for your help

Nicolas