Please help to write : Countif (range: >x and <y)

The second formula from Mr. Shorty is correct

=SUMPRODUCT(--(a10:z10>-3),--(a10:z10<0.4))

This should work with or without being Array entered (CTRL+SHIFT+ENTER)

Double check your entries to make sure they are valid.

Another option is to use this formula:

=COUNTIF(A10:Z10,"<0.4")-COUNTIF(A10:Z10,"<-3")

or this:

=COUNTIF(A10:H10,">-3")-COUNTIF(A10:H10,">0.4")

Good Luck