I think it's time for some more puzzles. I got these ones out of a book called Mathematical Puzzling by A. Gardiner. I have no idea where this book came from. I think my mum gave it to me... Anyhoo! Puzzles :)
1. Take your house number and double it. Add 5. Multiply by 50. Then add your age, the number of days in the year, and subtract 615. The last two digits are your age, and the first two are your house number. Can you explain why?
2. If all the stars stand for the same number, can you complete: (*/*) - (*/6) = (*/12)?
3. If you start with the number 2 and stick an extra digit 1 at the beginning you get 12, which is exactly six times the number you started with.
Can you find a number so that when an extra digit 1 is written at the beginning you get 3 times the number you started with?
Can you find one so that the number you get is 5 times the number you started with?
Can you find one so that the number you get is 9 times the number you started with?
4. In the multiplication 6 x 2 = 3 all the digits are correct, but they are in the wrong places. The equation should be 2 x 3 = 6 (or 3 x 2 = 6). In each of the next three multiplications all the digits are correct, but some of them are in the wrong places. Can you put them right?
28 x 1 = 44
43 x 2 = 14
76 x 8 = 41
That's it for today. I'll try to get the answers out on Wednesday, but it may be later depending on how well my assignments go.