$a)-67.(1-301)-301.67$

$=67.[-(1-301)-301]$

$=67.(-1+301-301)$

$=67.(-1)$

$=-67$

$b)(-3879-3879-3879-3879).(-25)$

$=3879.(-4).(-25)$

$=3879.100$

$=387900$

$\mathrm{ttiticticktick\; hhohôhộhộ\; tớ}$

1 Evening class

2 Sick children

3 Homeless people

4 Street children

5 Bonors

6 Volunteers

7 Early people

8 Disabled people

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