Type or copy into C3
=IF(ISNUMBER(A3)*ISNUMBER(B3)=1,A3*B3,0)
This will result in a zero answer if one cell or both contain text.
It means IF the first multiplication is true (both cells contain numbers) or =1 here, THEN multiply a3*b3 , ELSE give a zero answer.
What other value do we give some unknown text times a number ?
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Edit:-
=IF(ISTEXT(A3)+ISTEXT(B3)=2,"All Text",IF(ISNUMBER(A3)+ISNUMBER(B3)=2,A3*B3,IF(ISNUMBER(A3)=TRUE,A3,B3)))
If both cells have numeric values, this will multiply A3 and B3 , if only one is numeric that will be the answer, if both are text the result will be 'All Text'.
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