1. ODD NUMBERS :
Explanation:
Once in a year: We have only 1 new year every year. (Might sound a little weird -:P) Take odd number out. Here’s only 1 (i.e. once).
Twice in a month : We have 4 weeks every month.
So, 4 weeks = 1st, 2nd, 3rd and 4th. Now take odd numbers out-> 1st & 3rd (i.e. twice).
Four Times in a week : We have 7 days in a week.
Now take odd numbers out 1, 3, 5 and 7 (i.e. four times).
Six Times in a day : We have 12 hours in a day.
Now take odd numbers out 1, 3, 5, 7, 9 and 11 (i.e. six times).
2. Letter ‘F’ :
Explanation:
Once in a year: 1 year = 12 months, i.e. February ->F
comes once while counting in the spelling of all months).
Twice in a month : 1 month has 4 weeks, i.e. First, Fourth -> ‘F’ comes twice in the counting of weeks in a month).
Four Times in a week : 1 week has 7 days i.e. First, Fourth, Fifth -> ‘F’ comes 4 times in the counting of days in a week).
Six Times in a day : 1 day has 24 hours i.e. Four, Five, Fourteen, Fifteen, Twenty-Four -> ‘F’ comes 6 times in the counting of hours in a day).
3. Letter 'E'
Explanation:
Once in the word ‘yEar’.
Twice "EvEry month".
Four times "EvEry wEEk".
Six times "EvEry wEEkend.