Mental calculation

Einstein is right :)

lets do it then

$${\frac{\left({\mathtt{4}}{\mathtt{\,\times\,}}{\mathtt{5}}\right)}{\left({\mathtt{\,-\,}}{{\mathtt{1}}}^{{\mathtt{2}}}{\mathtt{\,\small\textbf+\,}}{\mathtt{5}}\right)}}$$

$$=\frac{20}{(1 + 5)}$$

$$=\frac{20}{6}$$

$$=\frac{5}{3}$$

now i hope you can do the rest yourself!

no Rosala

$$-1^2=-1$$

think about it, what is   $$100-3^2$$

it is 100-9=91

the - sign is NOT squared :)

The rest of your answer is correct :)

Precisely.

$${\mathtt{\,-\,}}\left({{\mathtt{1}}}^{{\mathtt{2}}}\right) = -{\mathtt{1}}$$ but

$${\left(-{\mathtt{1}}\right)}^{{\mathtt{2}}} = {\mathtt{1}}$$

So $${\frac{\left({\mathtt{4}}{\mathtt{\,\times\,}}{\mathtt{5}}\right)}{\left({\mathtt{\,-\,}}{{\mathtt{1}}}^{{\mathtt{2}}}{\mathtt{\,\small\textbf+\,}}{\mathtt{5}}\right)}} = {\frac{{\mathtt{20}}}{\left({\mathtt{\,-\,}}{\mathtt{1}}{\mathtt{\,\small\textbf+\,}}{\mathtt{5}}\right)}} = {\frac{{\mathtt{20}}}{{\mathtt{4}}}} = {\mathtt{5}}$$

So melody he gave another suggestion? Is that right?

I'm ALWAYS right ! Just kidding.