How to Add and Subtract Integers: Word Problems

How to Add and Subtract Integers: Word Problems

To solve an integer word problem, identify the starting value, describe each change with a signed number, and write an expression before calculating. First check what the question asks: a final value, a signed change, or a distance between two values. These can use the same numbers but give different answers.

How to choose addition or subtraction

  1. Choose a reference point. Zero might mean sea level, no money owed, or no points. A value below the reference is negative; a value above it is positive.
  2. State what you need to find. For a final value, combine the starting value and each signed change. For a signed change, calculate final value minus starting value. For a distance or gap, report the nonnegative separation.
  3. Write the expression, then calculate. Replace subtraction with addition of the opposite: a − b = a + (−b). For addition, same signs mean add the magnitudes and keep the sign; different signs mean subtract the smaller magnitude from the larger and keep the larger magnitude’s sign.
  4. Answer in context. Include units and explain a negative result. Check whether your answer agrees with the direction of the change.

Avoid relying on keywords alone. “The temperature fell” describes a negative change, but “How far did it fall?” asks for a positive amount. Similarly, a negative starting balance does not turn a deposit into a withdrawal.

Worked integer word problems

1. Temperature: find the final value

At sunrise, the temperature is −6°C. It rises 9°C. What is the new temperature?

Translate: start at −6 and add the rise: −6 + 9.
Calculate: 9 − 6 = 3, with a positive sign.
Answer: the temperature is 3°C. On a number line, moving nine units right from −6 lands at 3.

2. Money: combine a deposit and withdrawal

A bank balance is −$18. A $45 deposit is followed by a $32 withdrawal. What is the final balance? Ignore fees.

Translate: −18 + 45 − 32.
Calculate: −18 + 45 = 27, then 27 − 32 = −5.
Answer: the balance is −$5, so the account is overdrawn by $5. The deposit raises the balance; the withdrawal lowers it.

3. Elevation: find a signed change

A diver moves from −12 meters to −5 meters relative to the water’s surface. What is the change in position?

Translate: final minus starting position: −5 − (−12).
Calculate: −5 + 12 = 7.
Answer: the change is +7 meters: the diver rose 7 meters and is still 5 meters below the surface. Both positions are negative, but the change is positive.

4. Temperature: distinguish change from difference

The temperature falls from 4°C to −7°C. What is the signed change, and how many degrees did it fall?

Signed change: −7 − 4 = −11°C.
Amount of the fall: 11°C.
Check: 4 + (−11) = −7. The negative sign describes the direction; the positive amount describes the size of the fall.

Try three integer word problems

Write an expression and an answer with units before opening the solutions.

  1. A game score starts at −8 points. You gain 15 points, then lose 6. What is the final score?
  2. An elevator moves from floor −3 to floor 5. Each consecutive floor is one level apart. How many levels does it move, and in which direction?
  3. The temperature changes from −2°C to −9°C. Find the signed change and the amount of the drop.
Show answers and explanations
  1. 1 point. −8 + 15 − 6 = 7 − 6 = 1.
  2. 8 levels upward. 5 − (−3) = 5 + 3 = 8. The final floor is 5; the distance traveled is 8 levels.
  3. Signed change: −7°C; drop: 7°C. −9 − (−2) = −9 + 2 = −7. Check: −2 + (−7) = −9.

What to practice next

If the arithmetic is the difficult part, review integer addition and subtraction rules before trying another word problem. For printable skill practice, use the free Pre-Algebra worksheet collection; choose the integer topic you need rather than treating the entire collection as word-problem practice.

Use the free Pre-Algebra learning hub for related review. If you want a book for a broader study routine, preview Pre-Algebra for Beginners before choosing it. Check the sample’s level and format against your needs.

Original price was: $27.99.Current price is: $17.99.
Satisfied 92 Students

Further reading: OpenStax Prealgebra 2e: Subtract Integers, including subtraction in applications. The worked problems and practice above are original examples.

Related to This Article

What people say about "How to Add and Subtract Integers: Word Problems"?

No one replied yet.

Leave a Reply