《2025年同步轻松练习七年级数学上册人教版》

例1 把下列各式写成乘方运算的形式：
(1)$6× 6× 6× 6$； (2)$2.1× 2.1$；
(3)$(-3)× (-3)× (-3)× (-3)× (-3)$；
(4)$\dfrac{1}{2}× \dfrac{1}{2}× \dfrac{1}{2}× \dfrac{1}{2}× \dfrac{1}{2}$；
(5)$\left(-\dfrac{1}{2}\right)× \left(-\dfrac{1}{2}\right)× \left(-\dfrac{1}{2}\right)× \left(-\dfrac{1}{2}\right)$；
(6)$-\dfrac{1}{3}× \dfrac{1}{3}× \dfrac{1}{3}× \dfrac{1}{3}× \dfrac{1}{3}$.

答案： 解
(1)$6× 6× 6× 6 = 6^{4}$.
(2)$2.1× 2.1 = 2.1^{2}$.
(3)$(-3)× (-3)× (-3)× (-3)× (-3) = (-3)^{5}$.
(4)$\dfrac{1}{2}× \dfrac{1}{2}× \dfrac{1}{2}× \dfrac{1}{2}× \dfrac{1}{2} = \left(\dfrac{1}{2}\right)^{5}$.
(5)$\left(-\dfrac{1}{2}\right)× \left(-\dfrac{1}{2}\right)× \left(-\dfrac{1}{2}\right)× \left(-\dfrac{1}{2}\right) = \left(-\dfrac{1}{2}\right)^{4}$.
(6)$-\dfrac{1}{3}× \dfrac{1}{3}× \dfrac{1}{3}× \dfrac{1}{3}× \dfrac{1}{3} = -\left(\dfrac{1}{3}\right)^{5}$.