One option
Complete the series
Which one of the following numbers complete the series?
5 - 9 - 7 - 11 - 13 - 17 - 21 - 25 - 57 - ......
Which one of the following numbers complete the series?
5 - 9 - 7 - 11 - 13 - 17 - 21 - 25 - 57 - ......