Calcolare il valore delle seguenti espressioni:

Esercizio 1 \[ -4+5\times\left(-7\times2\right)= \] \[ -4+5\times\left(-14\right)= \] \[ -4-70=-74 \] Esercizio 2 \[ -2-3\times\left[-4\times\left(-5+1\right)+2\times8\div\left(-4\right)\right]= \] \[ -2-3\times\left[-4\times\left(-4\right)+16\div\left(-4\right)\right]= \] \[ -2-3\times\left[+16-4\right]= \] \[ -2-3\times\left[+12\right]= \] \[ -2-36=-38 \] Esercizio 3 \[ \left\{ -3\times\left[\left(-6+5\right)+2\times\left(-3\right)\right]\div\left(-7\right)\right\} +\left[2\times\left(5+1\right)+2\times6\div\left(-3\right)\right]= \] \[ \left\{ -3\times\left[-1-6\right]\div\left(-7\right)\right\} +\left[2\times6+12\div\left(-3\right)\right]= \] \[ \left\{ -3\times 1\right\} +\left[12-4\right]= \] \[ -3+8=5 \] Esercizio 4 \[ \left\{ 2\times\left[\left(-3+5\right)+2\times4\right]\div\left(-5\right)\right\} -3= \] \[ \left\{ 2\times\left[2+2\times4\right]\div\left(-5\right)\right\} -3= \] \[ \left\{ 2\times\left[2+8\right]\div\left(-5\right)\right\} -3= \] \[ \left\{ 2\times10\div\left(-5\right)\right\} -3= \] \[ \left\{ 20\div\left(-5\right)\right\} -3= \] \[ -4-3=-7 \]