91Ó°ÊÓ

Problem 63

Insert one set of parentheses in the expression \(6-12 \div 2 \cdot 3-5^{2}\) to make the equation true. $$6-12 \div 2 \cdot 3-5^{2}=-18$$

Problem 64

Write the expression in words. $$-a-b$$

Problem 72

Divide. $$(-72) \div(-9)$$

Problem 73

Simplify. $$-(-z)$$

Problem 76

Write the statement "the opposite of negative \(a\) is \(b\) " in symbols. Does \(a\) equal \(b\), or are they opposites?

Problem 81

Subtract. $$6-9$$

Problem 82

Subtract. $$-7-2$$

Problem 83

Divide. $$-91 \div(-7)$$

Problem 84

Subtract. $$7-(-2)$$

Problem 85

Subtract. $$3-(-4)$$