Google-sheets – Formula not working on Google Sheets #error! Formula Parse Error

In Google Sheets, you need to wrap small in arrayformula so it produces an array:

=average(arrayformula(small(D2:BD2, {1,2,3,4,5,6,7,8,9,10})))

There is an alternative solution, which is shorter and scales better if you will need 100 smallest instead of 10 smallest numbers:

=average(array_constrain(sort(D2:BD2), 10, 10))

Here, sort sorts the array in the increasing order. The array_constrain limits the output to at most 10 rows and 10 columns, which in practice means 10 smallest elements, regardless of whether your data was in a row or in a column.

There is nothing wrong with the formula so either:

• for the sheet's locale either the language or choice of delimiter is unsuitable (or both are).

• the formula in the sheet incorporates characters that are not displayed (and have not been copied into the OP above).

The latter tends to happen when formulae are copied out of Comments on SE (when invisible line breaks may be copied across). They can be seen if formulae are copied into Word or other suitable software.