Question 831070
{{{7}}} is 1 less than the base, so it is just
like {{{9}}} in base {{{10}}}
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Likewise, the number after {{{7}}} in the base {{{8}}}
is {{{10}}}. This {{{10}}} represents {{{8}}} in the base {{{10}}}
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So, the 3 numbers in base {{{8}}} which follow {{{7}}}
are {{{ 10}}}, {{{11}}}, and {{{12 }}} ( answer )
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In base {{{10}}} these numbers would be 
{{{8}}},{{{9}}}, and {{{10}}}