Numerical expressions are combinations of numbers and mathematical operators without an equal sign (=), while equations have an equal sign indicating that two things are equal.
To write a numerical expression for a given description, you need to identify the mathematical operations involved and use appropriate mathematical operators (+, -, *, /) to represent those operations.
You can compare two numerical expressions by observing patterns between them. Look for relationships between the operations involved and use symbols (<, >, =) to indicate which expression is greater or smaller.