1. 计算：
(1) $-\dfrac{5}{6}+\left|-\dfrac{2}{3}\right|$；
(2) $4.75-[-(2\dfrac{1}{2}+10\dfrac{2}{3})+3\dfrac{1}{2}]-5\dfrac{3}{4}$；
(3) $\dfrac{2}{5}-\left|-1\dfrac{1}{2}\right|-(+2\dfrac{1}{4})-(-2.75)$；
(4) $(-2.15-6.65)-[(2\dfrac{4}{7}-4\dfrac{3}{7})+(-8)]$；
(5) $(-\dfrac{2}{3})+\left|0-5\dfrac{1}{6}\right|+\left|-4\dfrac{5}{6}\right|+(-9\dfrac{1}{3})$；
(6) $\left|\dfrac{1}{3}-\dfrac{1}{2}\right|+\left|\dfrac{1}{4}-\dfrac{1}{3}\right|+\left|\dfrac{1}{5}-\dfrac{1}{4}\right|+\dots+\left|\dfrac{1}{2022}-\dfrac{1}{2021}\right|$。

(1) $-\dfrac{1}{6}$
(2) $8\dfrac{2}{3}$
(3) $-\dfrac{3}{5}$
(4) $\dfrac{37}{35}$
(5) 0
(6) $\dfrac{505}{1011}$
【解析】原式$=[-(\dfrac{1}{3}-\dfrac{1}{2})]+[-(\dfrac{1}{4}-\dfrac{1}{3})]+[-(\dfrac{1}{5}-\dfrac{1}{4})]+\dots+[-(\dfrac{1}{2021}-\dfrac{1}{2020})]+[-(\dfrac{1}{2022}-\dfrac{1}{2021})]=(\dfrac{1}{2}-\dfrac{1}{3})+(\dfrac{1}{3}-\dfrac{1}{4})+(\dfrac{1}{4}-\dfrac{1}{5})+\dots+(\dfrac{1}{2020}-\dfrac{1}{2021})+(\dfrac{1}{2021}-\dfrac{1}{2022})=\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{5}+\dots+\dfrac{1}{2020}-\dfrac{1}{2021}+\dfrac{1}{2021}-\dfrac{1}{2022}=\dfrac{1}{2}-\dfrac{1}{2022}=\dfrac{1011}{2022}-\dfrac{1}{2022}=\dfrac{1010}{2022}=\dfrac{505}{1011}$。

2. 计算：
（1）$19+298+3997+4996$；
（2）$89+899+8999+89999-9-99-999-9999$。

(1) 54310
【解析】原式$=(20-1)+(300-2)+(4000-3)+(50000-4)=20+300+4000+50000+(-1)+(-2)+(-3)+(-4)=54320-10=54310$。
(2) 88880
【解析】原式$=(89-9)+(899-99)+(8999-999)+(89999-9999)=80+800+8000+80000=88880$。