第16页

信息发布者:
$\begin{aligned} &159+268+132\\ =&159+(268+132)\\ =&159+400\\ =&559 \end{aligned}$
$\begin{aligned} &139+(133-69)\\ =&139-69+133\\ =&70+133\\ =&203 \end{aligned}$
$\begin{aligned} &556-207\\ =&556-200-7\\ =&356-7\\ =&349 \end{aligned}$
$\begin{aligned} &37×102\\ =&37×(100+2)\\ =&37×100+37×2\\ =&3700+74\\ =&3774 \end{aligned}$
$\begin{aligned} &6300÷35÷2\\ =&6300÷(35×2)\\ =&6300÷70\\ =&90 \end{aligned}$
$\begin{aligned} &340×101-10×34\\ =&340×101-1×340\\ =&340×(101-1)\\ =&340×100\\ =&34000 \end{aligned}$
​$2$​千米​$=2000$​米
​$(56+48)×18=1872($​米​$)$​
​$2000-1872=128($​米​$)$​
答:两人相距​$128$​米。
​$(56+48)×21=2184($​米​$)$​
​$2184-2000=184($​米​$) $​
答:两人相距​$184$​米。
12
5
15

$\begin{aligned} (120-12×5)÷15&=60÷15\\ &=4(天) \end{aligned}$