Numbers/Rounding and estimating

Notice: Incomplete

Rounding
There are two main types of rounding, directed rounding and rounding to the nearest integer.

Directed Rounding
Directed rounding is when one rounds all numbers in the same direction. There are four types, rounding up, rounding down, rounding towards zero and rounding away from zero.

Rounding Up
To round up, you round all numbers to the integer after it.

Examples:

-1.7 rounds to -1

-1.3 rounds to -1

1.3 rounds to 2

1.7 rounds to 2

Rounding Down
To round down, you round all numbers to the integer before it.

Examples:

-1.7 rounds to -2

-1.3 rounds to -2

1.3 rounds to 1

1.7 rounds to 1

Rounding Towards Zero
To round towards zero, you round all numbers to the nearest integer that is closer to zero.

Examples:

-1.7 rounds to -1

-1.3 rounds to -1

1.3 rounds to 1

1.7 rounds to 1

Rounding Away From Zero
To round away from zero, you round all numbers to the nearest integer that is further from zero.

Examples:

-1.7 rounds to -2

-1.3 rounds to -2

1.3 rounds to 2

1.7 rounds to 2

Rounding To the Nearest Integer
Rounding to the nearest integer is self-explanatory. The problem is that some numbers don't have a 'nearest integer', notably, the numbers that are halfway between integers.