Questions: Valeria ottiene 1 punto per ogni espressione corretta, 0 punti se non dà la soluzione, -0,5 punti se la risposta è errata. Quanti punti ha totalizzato? Correggi gli errori e completa i calcoli non fatti. a. 12-(+3)·(-2)+5·(-4)-9=-11 b. -7+(-6)·(+7)·(-1)-11+3=-57 c. 8-(-13)+(-5)·(-4)·(-2)-14=-3 6+(-9)·(-3)+(-4)·(-9)+11= -4-(-2)·(-11)-(+6)·(-5)=-4 15-3-6·(-5)·(+1)-8·(-4)=

Solution Steps

To determine Valeria's total points, we need to evaluate each expression and compare the result with her answer. Points are awarded based on the correctness of her answers.

1. Evaluate each expression.
2. Compare the evaluated result with Valeria's answer.
3. Assign points based on the comparison:
   • 1 point for a correct answer.
   • 0 points for no answer.
   • -0.5 points for an incorrect answer.
4. Sum the points to get the total.

For the first expression \( 12 - (+3) \cdot (-2) + 5 \cdot (-4) - 9 \): \[ 12 - 3 \cdot (-2) + 5 \cdot (-4) - 9 = 12 + 6 - 20 - 9 = -11 \] Valeria's answer is \(-11\), which is correct. Therefore, she earns \(1\) point.

For the second expression \( -7 + (-6) \cdot (+7) \cdot (-1) - 11 + 3 \): \[ -7 - 42 - 11 + 3 = -57 \] Valeria's answer is \(-57\), which is correct. Therefore, she earns another \(1\) point.

For the third expression \( 8 - (-13) + (-5) \cdot (-4) \cdot (-2) - 14 \): \[ 8 + 13 - 40 - 14 = -33 \] Valeria's answer is \(-3\), which is incorrect. Therefore, she loses \(0.5\) points.

Adding the points from each expression: \[ 1 + 1 - 0.5 = 1.5 \]

Final Answer