John is the son of Jacob.
So,
Jacob is the_____of John's father?

The answer I give is yes, but what I mean is no. What was the question?

A man lives on the fifteenth floor of an apartment building. Every morning he takes the elevator down to the lobby and leaves the building. In the evening, he gets into the elevator, and, if there is someone else in the elevator, or if it was raining that day, he goes back to his floor directly. Otherwise, he goes to the tenth floor and walks up five flights of stairs to his apartment. Can you explain why he does this?

I can be cracked, made, told, and played. What am I?

How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

We have arranged an array of numbers below. What you have to do is use any kind of mathematical symbol you know excluding any symbol that contains a number like cube root. You can use any amount of symbols but you have to come up with a valid equation for all of them.

0 0 0 = 6
1 1 1 = 6
2 + 2 + 2 = 6
3 3 3 = 6
4 4 4 = 6
5 5 5 = 6
6 6 6 = 6
7 7 7 = 6
8 8 8 = 6
9 9 9 = 6

Rob is taller than Edwin, and Jurgen is shorter than Rob.
Of only one of the following statements, we now certainly know it is correct:

A.Edwin is taller than Jurgen
B.Jurgen is taller than Edwin
C.It cannot be determined if Jurgen or Edwin is the tallest.

Can you complete the sequence puzzle?

AR TA GE CA LE VI LI _

Which English verb becomes past tense just by rearranging the letters?

Below is the sum of symbols in each row and column in the figure. Analyzing the figure, can you find out the value of the symbols?