65 x 42 - 130 x 21 + 2013
= 2730 - 2730 + 2013
= 0 + 2013
= 2013
học tốt!!!
\(=65\cdot42-65\cdot2\cdot21+2013\)
\(=65\cdot42-65\cdot42+2013\)
\(=2013\)
dấu.là dấu nhân nha^_^
\(65\times42-130\times21+2013\)
\(=2730-2730+2013\)
\(=0+2013\)
\(=2013.\)