ELI5: Explain Like I'm 5

Field (algebra)

A field in algebra is like a playground for numbers, where we can add them, subtract them, multiply them, and divide them (except for when we are dividing by zero). We can have different types of numbers in a field, such as the whole numbers (0, 1, 2, 3...), the rational numbers (numbers that can be expressed as a fraction like 1/4, 3/5, etc.), and the real numbers (all possible numbers including fractions, radicals, and decimals).

Just like on a playground, we have some rules or laws when we play with these numbers in a field. For example, we have the commutative law, which means that if we add, subtract, or multiply two numbers, it doesn't matter what order we do it in. So 2 + 3 is the same as 3 + 2, and 4 x 5 is the same as 5 x 4.

We also have the distributive law, which means that if we multiply a number by a sum or difference, we can break it up into smaller parts. For example, 2 x (3 + 4) is the same as 2 x 3 + 2 x 4.

Another important rule when we are playing in a field is that each number has an opposite or a negative. This means that for every number we have, there is another number that we can add to it to get zero. For example, the opposite of 4 is -4 because 4 + (-4) = 0.

Finally, in a field we also have what is called a multiplicative inverse, which is a fancy way of saying that for every number (except zero), there is another number that we can multiply it by to get 1. For example, the inverse of 2 is 1/2, because 2 x 1/2 = 1.

So in summary, a field in algebra is a playground where we play with numbers and follow certain rules or laws, such as commutative and distributive laws. We also have negatives and inverses for each number to help us play with them in different ways.