Question 648723
It isn't stated exactly, but there must be a fixed
number of oranges that are being shared.
Let {{{ c }}} = the number of children
With each one getting 9 oranges, there are
{{{ 9c }}} oranges in all.
and If each child gets 6 oranges, there are
{{{ 6c + 18 }}} oranges in all.
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In both cases, the number of oranges hasn't
changed, so 
{{{ 9c = 6c + 18 }}}
{{{ 3c = 18 }}}
{{{ c = 6 }}}
There are 6 children
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check:
If each gets 9 oranges, that is {{{ 6*9 = 54 }}}
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If each gets 6 with 18 left over, that is
{{{  6*6 + 18 = 36 + 18 }}}
{{{ 36 + 18 = 54 }}}
OK