Wykonajmy obliczenia.

$\left(-2\right)-\left(-7\right)=-2+7=5$

$5-7=5+\left(-7\right)=-2$

$2-4=2+\left(-4\right)=-2$

$4-3=1$

$2+\left(-2\right)=0$

$\left(-3\right)-\left(-3\right)=-3+3=0$

$\left(-14\right)+11=-3$

$1-1=0$

$5-7=5+\left(-7\right)=-2$

$\left(-7\right)+7=0$

$\left(-7\right)-\left(-3\right)=\left(-7\right)+3=-4$

$5-5=0$

$1-6+5=-5+5=0$

$\left(-6\right)-\left(-6\right)=-6+6=0$

$12-17=12+\left(-17\right)=-5$

$\left(-2\right)-\left(-5\right)=-2+5=3$

$\left(-5\right)+6=1$

$4+\left(-6\right)=-2$

$\left(-2\right)-3=\left(-2\right)+\left(-3\right)=-5$