Approximate – Rounding

An approximation is anything that is similar, but not exactly equal, to something else.

Example: 

A route takes 56 minutes to be covered, thus, it can be considered «a one-hour journey». 

To estimate a number, amount or total, often rounding it off to the nearest 10 or 100.

Rounding Rules
more than 5 > up
less than 5 < down

For decimal fractions
1. Look at the digit in the place value to be rounded to.
2. Increase it by 1 if the digit to the right of it is 5 or more.
3. Leave it the same if the digit to the right of it is less than 5.
4. Remove everything to the right of the digit.

Example:
Round 1634.286 to 1 decimal place:    1634.286 ≈ 1634.3

When rounding to 10 or above there’s an important change to step 4.
4. Replace whole numbers to the right of the digit with zero(s), then remove everything to their right.

Examples:
Round 1634.286 to 10
1634.286 ≈ 1630
Round 1634.286 to 100
1634.286 ≈ 1600
Round 1634.286 to 1000
1634.286 ≈ 2000