例 计算下列各题：
(1)$(\dfrac{1}{3}-\dfrac{3}{10}+\dfrac{2}{5})× (-4)× 15$；
(2)$(-370)× (-\dfrac{1}{4}) + 0.25×24.5 - (-5\dfrac{1}{2})×25\%$。
[解答](1)$(\dfrac{1}{3}-\dfrac{3}{10}+\dfrac{2}{5})× (-4)× 15$
$= (\dfrac{1}{3}-\dfrac{3}{10}+\dfrac{2}{5})× (-60)$
$= \dfrac{1}{3}× (-60) - \dfrac{3}{10}× (-60) + \dfrac{2}{5}× (-60)$
$= -20 + 18 - 24$
$= -26$。
(2)$(-370)× (-\dfrac{1}{4}) + 0.25×24.5 - (-5\dfrac{1}{2})×25\%$
$= 370×\dfrac{1}{4} + 0.25×24.5 + \dfrac{11}{2}×0.25$
$= 370×0.25 + 24.5×0.25 + 5.5×0.25$
$= (370 + 24.5 + 5.5)×0.25$
$= 400×0.25$
$= 100$。

(1)$(\dfrac{1}{3}-\dfrac{3}{10}+\dfrac{2}{5})× (-4)× 15$
$= (\dfrac{1}{3}-\dfrac{3}{10}+\dfrac{2}{5})× (-60)$
$= \dfrac{1}{3}× (-60) - \dfrac{3}{10}× (-60) + \dfrac{2}{5}× (-60)$
$= -20 + 18 - 24$
$= -26$
(2)$(-370)× (-\dfrac{1}{4}) + 0.25×24.5 - (-5\dfrac{1}{2})×25\%$
$= 370×\dfrac{1}{4} + 0.25×24.5 + \dfrac{11}{2}×0.25$
$= 370×0.25 + 24.5×0.25 + 5.5×0.25$
$= (370 + 24.5 + 5.5)×0.25$
$= 400×0.25$
$= 100$