\(a,1357-\left(964+357\right)-\left(36+120\right)=1357-964-357-36-120\)
\(=1000-1000-120=-120\)
\(b,10000-\left(137+572\right)+\left(263-291\right)=10000-137-572+263-291\)
\(=10000-709-291+263=10000-1000+263=9000+263=9263\)
\(c,35\cdot125+35\cdot75-70\cdot50=35\cdot125+35\cdot75-35\cdot100\)
\(=35\cdot\left(125+75-100\right)=35\cdot100=3500\)
(\(\cdot\)là nhân nhé bạn)
\(d,2-4+6-8+...+98-100=-2-2-...-2\)
(50 số hạng -2)
\(=\left(-2\right)\cdot50=-100\)
Làm lại câu d:
\(d,2-4+6-8+...+98-1000=-2-2-...-2+98-1000\)
(49 số -2)
\(=\left(-2\right)\cdot49+98-1000=-98+98-1000=1000\)
