Once you have solved them (or gotten tired of trying to solve them and want to give up), highlight the white space under the question. I've written the answers there, but made the text white, so it won't show up until you highlight it. :)
1. Prove that seven is half of twelve.
Write twelve in Roman numerals - XII. Halve the number by drawing a line horizontally across its center. The upper half is VII.
2. Place three sixes together so as to make seven.
The answer to this is a fraction - I would write it as a fraction but Blogger won't let me! It's 6 6/6
4. Express 100 by repetition of the same figure six times over.
Another fraction one. 99 99/99 = 100.
5. What is the surest way of keeping water from entering your house?
Don't pay your water bill.
6. Five herrings were divided among five persons. Each had a herring and yet one remained in the dish. How was this managed?
The last of the five received his herring in the dish.
7. What gets bigger the more you contract it?
8. Prove that two sixes make eleven.
This is dependent on the use of Roman numerals. One six (VI) is placed above another six, but the latter in an inverted position, the combination making XI.
9. What speaks all languages?
10. You undertake to show another person something which you never saw before, which he never saw before, and which, after you both have seen it, no one else will ever see again. How is it to be done?
The puzzle is solved by cracking a nut, showing your interlocutor the kernel, then eating it.
11. How many times can you subtract 5 from 135?
Only once. After that it isn't 135 anymore.
12. You undertake to put something into a person's left hand which he cannot possibly take in his right. How is it to be done?
You place in the person's left hand his own right elbow, which, obviously, he cannot take in his right hand.
13. Take one from nineteen and leave twenty.
Write nineteen in Roman numerals - XIX. Remove the I and you have XX, which is twenty.
Did you get any of them wrong?
Do you have any puzzles for me? Leave them in the comments. :)
Happy May everyone!