## Simple solution

Try `=IF(TRIM(B1)="";"";B1*C1)`

## Know what you are doing!

Your habit of clearing a value by spacebar is a potential source for error. A space is not "nothing". You can't see it by itself, but it is there. NEVER use the space bar to "clear" a cell. Always use keys backspace or delete to remove content.

Calc will interpret a cell containing text and allow it in number context only in very special cases. Single space character is not one of those cases. It is a mess, as Lupp has elaborated good and well.

Hence, you need to know what type(s) of data you are working with.

The formula `=B1+C1`

is interpreted as "There are numbers in cell B1 and C1. Add them!" If one of the cells contain something not allowed in number context, Calc says "nope" and throws an error. This is by design. If one of the cells contain the text "123", it will be interpreted to the number 123 and included in the sum, because the formula insists that it be a number. An empty cell will add nothing, and an error will propagate to the result.

The formula `=SUM(B1;C1)`

is interpreted as "There may be numbers in the given cells. Add them up!" Cells containing numbers will be included in the sum. Cells containing text will be discarded. So, if one cell contains "123" represented as text, **it will add nothing to the sum**. Again, empty cells will add nothing, and errors will propagate.

A cell with one space will not match the empty string `""`

, but it will match the single character string `" "`

If you insist on using the spacebar to clear a value, you can compare with that.

Better, use the `TRIM()`

function, which will clear out "excess" spaces (leading, trailing and repeat spaces). This will be more robust, as it handles both empty cells, cells with one space and cells which (accidentally) contains multiple spaces. Hence, the simple solution above. If you still made it this far, good on you!

I solved the problem how to bypass it. Choose>Tools>Settings>LibreOfficeCalc>Formula>dot for Adjust (Converting text to numbers a.s.o...)>Specifics...>x for The value of the blanco string is zero. Formula; =IF(A1

B1=0;"";A1B1) Works Yess! Words are translated from finnish LibreOffice. The text may be idicativeMust be A1xB1. Multiplier signs has disappeared.