Desire one of the company to think of any number she chooses, provided it be even. Tell her to triple it, halve the product, triple this half, and then tell you how many times nine will go into it. Multiply this by two, and it will be the number thought of. Thus, suppose 4 to be the number ; you triple it, making 12 ; halve this product, leaving 6; again triple this, making 18, in which 9 will go twice: this"twice"multiplied by 2 gives you 4, the number thought of. Or, to give another example, suppose 6 to be the number; triple it, 18; halve it, 9; triple it again, 27. You ask how many times 9 will go in it, and, being told 3 times, multiply it by 2, and the answer is 6.