\(abcd+abc+ab+a=2236\left(đk:0< a< 3\right)\)
\(a\times1000+b\times100+c\times10+d+a\times100+b\times10+c+a\times10+b+a=2236\)
\(\Rightarrow\left(a\times1000+a\times100+a\times10+a\right)+\left(b\times100+b\times10+b\right)+\left(c\times10+c\right)+d=2236\)
\(\Rightarrow a\times1111+b\times111+c\times11+d=2236\)
\(b\times111+c\times11+d\)lớn nhất \(=9\times111+9\times11+9=1107\)
\(\Rightarrow a\times1111\)nhỏ nhất \(=2236-1107=1129.\)Vậy \(a>1\)và \(a< 3\)
\(\Rightarrow a=2\)
khi \(a=2\Rightarrow2\times1111+b\times111+c\times11+d=2236\)
\(\Rightarrow b\times111+c\times11+d=2236-2222\)
\(\Rightarrow b\times111+c\times11+d=14\)
\(b=0;c=1;d=3\)
Vậy : \(abcd=2013\)
