Math
Raise me none, and I'm unbeaten. Raise me once, I am as well. Raise me thrice, and I am eaten. All said right, but wrongly spelled. Who am I?
Math
Five times the difference of twice a number and three, decreased by the sum of this number and eight, equals thirteen.
Math
The ages of a father and son add up to 66. The father's age is the son's age reversed. How old could they be?
Math
Find the four-digit number in which the first digit is one-fourth of the last digit, the second digit is 6 times the first digit, and the third digit is the second digit plus 3.
