Originally, each country had its own, and rather poorly reproducible, unit of luminous intensity; it was necessary to wait until 1909 to see a beginning of unification on the international level, when ... Continue reading
A circle is what you get if you take a straight line and bend it around so that its ends touch. You can demonstrate this by taking a piece of stiff wire and doing just that: bring the ends of the wire ... Continue reading
A prime number is a number that is divisible only by one and by itself. Factors are numbers that can be divided into a number with no remainder. The factors of 18 are the numbers 1, 2, 3, 6, 9, and ... Continue reading
The mathematical term 'cube' comes from the three-dimensional shape of the same name. A cube shape has three dimensions of length, width, and height, all equal and at angles of 90 to each other. Put ... Continue reading
