Project ID:
7200020078
Accepted:
Tipo:
Layout:
Question:
Calcula la expresión numérica mentalmente y emparéjala con el resultado correspondiente.
$$\,$$
Pista:
$$
\begin{align}
71^2−70^2 & =(71−70)(71+70)=1\cdot 141=141 \cr
71 \cdot 69 & =(70+1)(70−1)=70^2−1^2=4900−1=4899
\end{align}
$$
Questions Title:
Expresiones:
Answers Title:
Soluciones:
Question 1:
$91 \cdot 89$
Answer 1:
$8099$
Question 2:
$36 \cdot 24$
Answer 2:
$864$
Question 3:
$82 \cdot 78$
Answer 3:
$6396$
Question 4:
$170^2−70^2$
Answer 4:
$24000$
Question 5:
$102^2−98^2$
Answer 5:
$800$
Question 6:
$\left(\frac{15}{29}\right)^2−\left(\frac{14}{29}\right)^2$
Answer 6:
$\frac{1}{29}$
Question 7:
$\sqrt{52^2−48^2}$
Answer 7:
$20$
Question 8:
$\sqrt{218^2−182^2}$
Answer 8:
$120$