91Ó°ÊÓ

Which property of real numbers justifies each statement? $$3+x=x+3$$

Simplify each expression. $$\left|\frac{3}{5}+\left(-\frac{4}{5}\right)\right|$$

Place one of the symbols \(=,<,\) or \(>\) in each box to make a true statement. $$5+6\square13-1$$

Explain why division is not commutative.

Suppose there were no numbers other than the odd integers. \(\cdot\) Would the closure property for addition still be true? \(\cdot\) Would the closure property for multiplication still be true? \(\cdot\) Would there still be an identity for addition? \(\cdot\) Would there still be an identity for multiplication?

Perform each operation. SEE EXAMPLES 10,11 , and \(12 .\) (OBJECTIVE 5 ) $$345.213-27.35$$

A rope \(x\) feet long is cut into 5 equal pieces. Find an expression for the length of each piece.

Write each sentence as a mathematical expression. \(\sqrt{2}\) is approximately equal to 1.41

Use signed numbers and one or more operations to answer each question. Justin worked all day mowing lawns and was paid \(\$ 8\) per hour. If he had \(\$ 94\) at the end of an 8 -hour day, how much did he have before he started working?

What is the purpose of using variables? Why aren't ordinary numbers enough?