One-Step Equations Rational Numbers Positive

Why do you divide by 5?

• To undo division, you must multiply.

• To balance the equation, you must divide by 5 on both sides.

• To undo multiplication, you must divide.

• To balance the equation, you must multiply by 5 on both sides.

Why do you multiply by 7?

• To undo division, you must multiply.

• To balance the equation, you must divide by 7 on both sides.

• To undo multiplication, you must divide.

• To balance the equation, you must multiply by 7 on both sides.

Why do you multiply by 8?

• To undo division, you must multiply.

• To balance the equation, you must divide by 8 on both sides.

• To undo multiplication, you must divide.

• To balance the equation, you must multiply by 8 on both sides.

Evaluate: x-5 = -12

• 17

• -17

• 7

• -7

Andrew has saved $55 toward the purchase of an IPOD. The IPOD costs $145. Which equation represents the amount Andrew needs to save to by the IPOD?

• 55 + x = 145

• 145x = 55

• 55 - x = 145

• 145 (55) = x

Last Friday Cicely had $22.50. Over the weekend she received some money for cleaning out the attic. She now has $32. Which equation represents how much money she received?

• 22.50/ x = 32

• 32/ 22.50 = x

• 22.50 + x = 32

• 32 - x = 22.50

WRITE AN EQUATION
After paying $5.12 for a salad, Norachai has $27.10. How much money did he have before buying the salad?

• 27.10+5.12=x

• 27.10-5.12=x

• x-5.12=27.10

• 5.12+x=27.10

Solve the equation. Check your solution.

• 24

• ¹⁴⁷/₈ or 18 ³/₈

• 168

• -24

• add both sides by 2.17

• subtract both sides by 2.17

• multiply both sides by 2.17

• divide both sides by 2.17