To write; -12.405 as a mixed number:
First keep the whole number aside
That is; you shoul keep 12 aside
Then you will be left with 0.405
Write 0.405 over 1
That is;
[tex]\frac{0.405}{1}[/tex]Multiply 1000 be the numerator and denominator
That is;
[tex]\frac{0.405\text{ }\times1000}{1\text{ }\times1000}[/tex][tex]=\frac{405}{1000}[/tex]We can go ahead and reduce the fraction;
[tex]=\frac{81}{200}[/tex]Hence the mixed number is;
[tex]-12.405\text{ = -12}\frac{81}{200}[/tex]