The phrase "a number plus three less than five" can be written as a mathematical expression.

• "A number" represents a variable, which we'll call $x$.
• "Three less than five" means $5 - 3$, which equals 2.

So, the expression is: $x + 2$

This represents a number plus 2.

Would you like me to help you with solving this in a specific context, or is there something more you'd like to explore?

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Here are 5 related questions you might find interesting:

1. How can I represent a number plus five more than ten algebraically?
2. What happens if you subtract a number from three less than five?
3. How do you solve the equation $x + 2 = 10$?
4. What is the significance of variables in algebraic expressions?
5. How do you handle operations with variables in equations?

Tip: Always make sure to break down word problems into smaller steps to easily translate them into mathematical expressions!