9, 5, 18, 21 ? 30, 36, 36, 42, 49 what is the missing number??
9, 15, 18, 21, ?, 30, 36, 42, 59, ...
The pattern for this sequence is +6, +3, +6, +3, so the missing number will be 21 + 6, or 27.
the pattern is +6 then
the pattern is +6 then +3 so, 21+6=27.