We also have some math-type calculators to light your way in some of those mathematical dark corners, especially for those curious numerates.
Which Day This Date lets you calculate the day of week of any date.
Factors of a number - Some numbers are divisible by numbers other than themselves; some aren't. See The Nature Of Numbers.
Percentage change - It all depends on where you start - at the beginning or the end.
At some time, I suppose, it may be useful to know the Primes between two numbers. It was interesting developing this calculator, nevertheless.
Convert decimal to fraction - For measurement purposes, it is sometimes more practical to think in terms of fractions - using a measuring tape. Some decimals have an exact fraction equivalent; others can have only a near approximation depending on the number of decimal points.
Add, subtract, multiply, divide Fractions
LCM/HCF - The Lowest Common Multiple and the Highest Common Factor.
Multiplication tables: You can see the additive nature of multiplication using any table you wish.
There are some other exploratory calculators.
Square roots progress in a predictable order so that we can progress from one known square root to any other in an additive manner. This Square root progression calculator develops and demonstrates this method.
With this Mental multiplication exercise we develop some of the characteristics we know about square roots and use these to multiply two odd or even-numbers mentally.
These are just a few of the utilities available on this site and the number is in constant growth. A full list can be seen on the left.