Basic Arithmetic and Inverse Operations

In maths, dividing by zero is undefined. The divisor tells you how many equal parts to share a total into. A divisor of zero means there is nobody to share the total with. Picture 12 donuts and zero friends to share them with: the question simply has no answer.

A simple example is 2 plus 5 equals 7, and then 7 minus 5 equals 2. The subtraction has cancelled out the addition, returning you to the original number. Multiplication and division work the same way: 2 times 3 equals 6, and 6 divided by 3 equals 2.

The answer to a multiplication is called the product. For example, in 3 multiplied by 6 equals 18, the number 18 is the product. The two numbers being multiplied, 3 and 6, are called factors. One factor is the multiplier and the other is the multiplicand.

A clear example is 6 plus 6 plus 6 equals 18. The three sixes are the summands, the numbers being added together, and 18 is the sum, the total result. Adding the same number repeatedly like this links directly to multiplication, which is 3 times 6.

Multiplication is like making copies of the same group. If three friends each bring 6 donuts, you have 3 copies of 6 donuts, which gives 18 in total. Instead of adding 6 plus 6 plus 6, you can shorten it and say 3 times 6 equals 18.