Question

Find the values of the letters in the following and give reasons for the steps involved.
$A1\underset{–}{+1B}\underset{–}{B0}$

Answer 1

If $1+B=0$, then $B$ has to be $9$.

With $B=9$,

Now, we have condition $A+1+1($carry over$)=B$.

i.e. $A+2=9$

So,

$A=7,B=9$