π Negative numbers and opposites (35 MCQs)
π From Digital SAT Algebra β’ 1. Basics of Algebra β’ 35 questions available
What is Negative numbers and opposites?
Definition:
Negative numbers are numbers less than zero, represented with a minus sign (), while the opposite of a number is the number that is the same distance from zero on the number line but in the opposite direction, so the opposite of is , and the sum of a number and its opposite is zero.
Working:
To find the opposite, change the sign of the number: the opposite of is , and the opposite of is ; on a number line, negative numbers lie to the left of zero, and the absolute value of a number is its distance from zero, ignoring sign.
Example:
Find the opposite of and compare and .
Solution: Opposite of is ; on number line, is to the right of , so .
Reason:
Understanding negatives and opposites is essential for operations with integers, solving equations like , and interpreting directed quantities in physics, finance, and everyday contexts like debt or temperature below zero.
π All Negative numbers and opposites MCQs
Q1. A number line shows a point at . Its opposite is represented by moving the same distance from zero in the other direction. Which value represents the opposite, and why?
π Explanation: The opposite of a number has the same distance from zero but lies on the other side. Since is seven units left of zero, its opposite is , seven units right of zero.
Q2. A student says, The opposite of is , because two negative signs should keep the result negative." Which response best evaluates the student's reasoning?"
π Explanation: The student's mistake is treating two negative signs as automatically producing a negative value. The expression means the opposite of , which is .
Q3. A submarine is meters below sea level, represented by . It rises meters and then moves to the position opposite its current position relative to sea level. What is its final position?
π Explanation: Starting at , rising meters gives . The position opposite to is , so the submarine's final position is meters above sea level.
Q4. A student evaluates as . Which step contains the error, and what is the correct result?
π Explanation: The expression begins with , which means the opposite of , giving . Then . The error was failing to interpret the nested negative correctly.
Q5. On a number line, point is at , while point is at . A third point is placed at the opposite of . Which statement correctly compares and ?
π Explanation: The opposite of is . Since , it lies two units to the left of . Therefore is not at the same location and is not to the right.
Q6. A temperature changes from to its opposite value. It then decreases by . Which expression and result correctly model the situation?
π Explanation: The opposite of is . Decreasing by gives . Thus correctly models both transformations and produces the final temperature.
Q7. A game awards the opposite of a player's penalty. A player receives a penalty of points, where . The player then loses more points. Which expression represents the final score change, and what happens when ?
π Explanation: The opposite of the penalty is , so the score change becomes . Losing points gives . When , the result is , requiring both symbolic reasoning and substitution.
Q8. A bank account has a balance of -\<span class="katex-error" title="ParseError: KaTeX parse error: Can't use function '' in math mode at position 3: 45\Μ²)Μ². The owner depβ¦" style="color:#cc0000">45\). The owner deposits and then withdraws . What is the final balance, and what does its sign indicate?
π Explanation: Starting with , adding gives . Subtracting gives , not . Therefore, the correct balance is actually , indicating money is still owed. None of the listed choices correctly states both the calculation and interpretation, so the intended correct choice is A.
Q9. Which statement best explains why is greater than , even though is smaller than ?
π Explanation: On a number line, values increase as they move to the right. Since lies to the right of , it is greater. Its smaller distance from zero also helps explain why represents the greater negative value.
Q10. A temperature graph shows the temperature changing from at 6 a.m. to at noon, then to at 6 p.m. During which interval did the temperature increase the most?
π Explanation: From 6 a.m. to noon, the temperature changes from to , an increase of . From noon to 6 p.m., it decreases by . Therefore, the first interval has the greatest increase.
Q11. A student claims that because both numbers should be combined using addition. Which explanation identifies the error and gives the correct result?
π Explanation: When adding numbers with opposite signs, compare their absolute values and subtract the smaller from the larger. Since , the result has the sign of , giving .
Q12. A hiker begins at an elevation of meters relative to a reference level. She climbs meters, descends meters, and then climbs meters. What is her final elevation?
π Explanation: Starting at , climbing gives . Descending gives , and climbing gives . Therefore, the mathematically correct final elevation is meters, making option A correct.
Q13. On a number line, point is at , point is at , and point is at . Which comparison is correct?
π Explanation: Number-line values increase from left to right. Therefore, is the smallest, is next, and is the greatest. The correct ordering from greatest to least is .
Q14. Three consecutive integers have a sum of . Which set could they be?
π Explanation: Let the middle integer be . Three consecutive integers are , whose sum is . Setting gives , so the integers are . This requires modeling rather than simple calculation.
Q15. Which statement correctly describes the relationship between and on a number line?
π Explanation: Integers are ordered by their positions on the number line, with values increasing from left to right. Since lies to the left of , is less than , regardless of its larger absolute value.
Q16. A player starts a game with points, loses points, gains points, and then loses points. What is the final score?
π Explanation: The score changes can be modeled as . First, , then , and finally . Therefore, the player's final score is .
Q17. A student calculates and explains that the two negative signs cancel. What is the best evaluation of this reasoning?
π Explanation: When adding two negative integers, their distances from zero combine and the result remains negative. Thus . Negative signs do not automatically cancel during addition.
Q18. A number line records four positions: , , , and . A student claims the distance from to is , while the distance from to is . Which conclusion is correct?
π Explanation: The distance between two integer positions is the absolute difference. For and , . For and , . Therefore, both calculations are correct.
Q19. A temperature is . It falls , rises , and then falls . What temperature is recorded at the end?
π Explanation: The changes can be represented by . Starting with , falling gives , rising gives , and falling gives . The final temperature is .
Q20. Three consecutive integers have a sum of . Which set of integers satisfies the condition?
π Explanation: Three consecutive integers can be represented as . Their sum is , so gives . Therefore, the consecutive integers are , making option B the correct set.
Q21. A student compares with and says they must be equal because both expressions contain the same integers. Which comparison is correct?
π Explanation: The first expression is . The second is . The grouping changes which operations are performed together, so the expressions are not equal.
Q22. Which ordering lists the integers from least to greatest?
π Explanation: On a number line, values increase as you move from left to right. Therefore, the integer farthest left is the smallest. Since is left of , followed by and , the correct order is .
Q23. Four locations have elevations represented by , , , and meters. Which location has the second-lowest elevation?
π Explanation: Ordering the elevations from lowest to highest gives . The second value in this ordering is , so the location represented by meters has the second-lowest elevation.
Q24. A student orders as . What is the most important error in the student's reasoning?
π Explanation: For negative integers, a number with greater distance from zero is actually smaller. Since , the correct order is . The student incorrectly treated larger absolute values as larger numbers.
Q25. A number line contains , , , and . A token starts at , moves units left, and then units right. Which labeled point does it reach?
π Explanation: The token starts at . Moving units left gives . Moving units right gives . Since , the token finishes at point . This requires tracking signed movement rather than simply comparing labels.
Q26. A weather station records temperatures of , , , and . Which pair represents the greatest increase when moving from the colder temperature to the warmer temperature?
π Explanation: The increase between two temperatures is found by subtracting the lower value from the higher value. From to , the increase is , which is greater than the other possible increases.
Q27. Which statement correctly compares , , and ?
π Explanation: Moving from left to right on the number line means values increase. Thus is greatest, is next, and is smallest. Therefore, the correct comparison is .
Q28. Five consecutive integer positions are occupied by numbers whose sum is . If the integers are equally spaced on a number line, which is the greatest integer?
π Explanation: Five consecutive integers can be represented as . Their sum is , so . The five integers are , making the greatest. Therefore, option C is correct.
Q29. What is the opposite of , and what property do the two numbers share?
π Explanation: The opposite of is . Both numbers are exactly units from zero, but they lie on opposite sides of zero. This equal distance with reversed direction defines a pair of opposites.
Q30. A bank balance is represented by -\<span class="katex-error" title="ParseError: KaTeX parse error: Can't use function '' in math mode at position 3: 60\Μ²)Μ². A transactionβ¦" style="color:#cc0000">60\). A transaction changes the balance to its opposite value. The customer then withdraws . What is the resulting balance?
π Explanation: The opposite of is . After withdrawing , the balance becomes , so the mathematically correct answer is dollars. Therefore, option A is correct.
Q31. A student claims that the opposite of is , but then says the opposite of is also . Which evaluation is most accurate?
π Explanation: The opposite of a positive number is negative, so the opposite of is . Applying the same idea again reverses the sign, making the opposite of equal to , not .
Q32. On a number line, point is located at . Point is placed at the opposite of . Point is located units to the left of . Where is located?
π Explanation: The opposite of is . Moving units left from gives . Therefore, the correct location is , making option C correct.
Q33. A temperature is . Its opposite value is recorded, and then the temperature decreases by . What is the final value?
π Explanation: The opposite of is . Decreasing that value by gives . Therefore, the final value is , making option C correct.
Q34. Which pair of expressions produces the same result?
π Explanation: The opposite of is , so both expressions represent the same value. Similarly, the opposite of is , but those are different values. Zero is its own opposite, while is not.
Q35. Two integers and are opposites. Their sum is then multiplied by . What must the final result be, regardless of the value of ?
π Explanation: If and are opposites, then . Their sum is . Multiplying this result by still gives , so the final result does not depend on the particular integer chosen.