why my calculator shows $10\%9=0.9$ When I search in Google it shows me correct result $10\%9=1$
But in my calculator I get $10\%9=0.9$ 
Let me know the reason soon and  if you have great solution that would be appreciated.
 A: Google (as well as a bunch of programming languages) interprets 10%9 as $10\mod 9$ and thus results in $1$.
a%n, or $a\mod n$, will have google find the $0\leq r<n$ such that there is an integer $k$ such that $kn+r=a$ (which is different than the usual $\text{mod}$, since those define equivalence classes, yet very similar).

Your calculator however assumes with a%n you mean "$a$ times $n$ percent" and will thus result in $a\cdot \frac{n}{100}$.
A: To compute $a\%n$ the way Google does, i.e. interpreting it as $a\mod n$, we can use the following formula:
$$a\%n=a\mod n=a - \left(\left\lfloor\frac an\right\rfloor \times n\right)$$
That is to say:


*

*Compute $\frac an$

*Round it down to the nearest integer

*Multipy it by $n$ 

*Subtract the result from the original $a$
For your example we would do:
\begin{align}10\%9&=10-\left(\left\lfloor\frac {10}{9}\right\rfloor \times 9\right)\\
&=10-\left(\left\lfloor1.\overline{111}\right\rfloor\times 9\right)\tag{Step $1$}\\
&=10-\left(1\times 9\right)\tag{Step $2$}\\
&=10-9\tag{Step $3$}\\
&=1\tag{Step $4$}\end{align}
