Learn to solve whole-number division equations.

Recall that multiplication and division are inverse operations Recall that multiplication and division are inverse operations. If an equation contains division, solve it by multiplying on both sides to “undo” the division.

Additional Example 1A: Solving Division Equations Solve the equation. Check your answer. x 7 = 5 x is divided by 7. x 7 = 5 7  x 7 = 7  5 Multiply both sides by 7 to undo the division. x = 35 Check x 7 = 5 35 7 = 5 ? Substitute 35 for x in the equation. 5 = 5 ?  35 is the solution.

Additional Example 1B: Solving Division Equations Solve the equation. Check your answer. p 6 13 = p is divided by 6. p 6 13 = 6  p 6 6  13 = Multiply both sides by 6 to undo the division. 78 = p Check p 6 13 = ? 78 6 13 = Substitute 78 for p in the equation. 13 = 13 ? 78 is the solution. 

Solve the equation. Check your answer. x 2 = 9 Check It Out: Example 1A Solve the equation. Check your answer. x 2 = 9 x is divided by 2. x 2 = 9 2  x 2 = 2  9 Multiply both sides by 2 to undo the division. x = 18 Check x 2 = 9 18 2 = 9 ? Substitute 18 for x in the equation. 9 = 9 ?  18 is the solution.

Solve the equation. Check your answer. p 4 72 = Check It Out: Example 1B Solve the equation. Check your answer. p 4 72 = p is divided by 4. p 4 72 = 4  p 4 4  72 = Multiply both sides by 4 to undo the division. 288 = p Check p 4 72 = ? 288 4 72 = Substitute 288 for p in the equation. 72 = 72 ? 288 is the solution. 

height of pine height of aspen = 3 Additional Example 2: Application At Elk Meadows Park an aspen tree is one- third the height of a pine tree. height of pine height of aspen = 3 The aspen tree is 14 feet tall. How tall is the pine tree? Let h represent the height of the pine tree. Substitute 14 for height of aspen. h is divided by 3. h 3 14 = 3  h 3 3  14 = Multiply both sides by 3 to undo the division. 42 = h The pine tree is 42 feet tall.

Jamie’s father weighs 190 pounds. Check It Out: Example 2 Jamie weighs one-half as much as her father. father’s weight Jamie’s weight = 2 Jamie weighs 95 pounds. How many pounds does her father weigh? Let w represent her father’s weight. Substitute 95 for Jamie’s weight. w is divided by 2. w 2 95 = 2  w 2 2  95 = Multiply both sides by 2 to undo the division. 190 = w Jamie’s father weighs 190 pounds.