A seven-year-old kid challenged his classmates that he can make the number one disappear by adding something to it.

How can he do that?

Replace the question mark with the correct number, given the pair of numbers exhibits a similar relationship?

? : 3839 :: 11 : 1209

You see me once in June, twice in November, and not at all in May. What am I?

Below, you can see some coding:
January = 1017
February = 628
March = 1335
April = 145
May = 1353
June = 1064
July = 1074
August = 186

Now deciphering the way it has been coded, can you find out how September will be coded?

In two decks of cards, what is the least amount of cards you must take to be *guaranteed* at least one four-of-a-kind?

Nodes are shown below and you need to connect them based on the following rule: Every node can be connected to the number of nodes inside them, i.e. the first node there is a value of 1 which indicates that the first node can connect to exactly one node only.Can you do it?

One is to three as three is to five and five is to four and four is the magic number.
What is the pattern?

What word does this rebus represent?

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What is the four-digit number in which the first digit is one-third the second, the third is the sum of the first two, and the last is three times the second?

Find out the missing number in the picture attached: