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About Integers — Class 7 Olympiad

Perform operations on integers, apply properties of addition and multiplication, and solve integer-based Olympiad puzzles. This topic is part of the Olympiad Class 7 mathematics syllabus (chapter: Module 1). On this page you can practice 59 questions across three difficulty levels — 20 easy, 20 medium, and 19 hard — each with a visual step-by-step solution, plus a timed 35-question mastery test with a live leaderboard. Worked examples and sample questions from the topic are below.

Integers — solved examples for Class 7 Olympiad

Example 1easy

An integer P is 7 units to the left of -3 on the number line. Another integer Q is 5 units to the right of P. What is the value of Q?
  1. A)-15
  2. B)-1
  3. C)-5
  4. D)-10

Step-by-step solution

  1. P is 7 units to the left of -3. This means P = -3 - 7.
  2. Calculating P: P = -10.
  3. Q is 5 units to the right of P. This means Q = P + 5.
  4. Calculating Q: Q = -10 + 5 = -5.

Answer: -5

Example 2medium

Find the value of P = 1 - 2 + 3 - 4 + 5 - 6 + ... + 99 - 100 + 101.
  1. A)-50
  2. B)51
  3. C)-51
  4. D)50

Step-by-step solution

  1. Group the terms in pairs: (1 - 2) + (3 - 4) + (5 - 6) + ... + (99 - 100) + 101.
  2. Each pair sums to -1: (-1) + (-1) + (-1) + ... + (-1) + 101.
  3. There are (100 / 2) = 50 such pairs. So, the sum of these pairs is 50 × (-1) = -50.
  4. Add the last term: -50 + 101 = 51.

Answer: 51

Example 3hard

Let P = (1 - 100) × (2 - 100) × (3 - 100) × ... × (200 - 100). What is the value of P?
  1. A)A) A very large negative number
  2. B)B) 0
  3. C)C) -100!
  4. D)D) 100!

Step-by-step solution

  1. The product P consists of terms in the form (n - 100) where n ranges from 1 to 200.
  2. As 'n' goes from 1 to 200, one of the terms will be (100 - 100).
  3. Since (100 - 100) = 0, and any number multiplied by zero is zero, the entire product P will be 0.
    P=(1100)×...×(100100)×...×(200100)=...×0×...=0P = (1-100) × ... × (100-100) × ... × (200-100) = ... × 0 × ... = 0

Answer: B) 0

Practice questions on Integers

  1. Q1.easy

    If 'm' and 'n' are two distinct integers such that |m| = |n|, then which of the following statements must be true?
    1. A)m + n = 0
    2. B)m × n > 0
    3. C)m - n = 0
    4. D)m is positive and n is negative
    Show answer

    Answer: m + n = 0

    Hint: If two distinct integers have the same absolute value, what does that imply about their relationship?

  2. Q2.easy

    What is the sum of all integers between -10 and 10 (exclusive)?
    1. A)-10
    2. B)0
    3. C)10
    4. D)20
    Show answer

    Answer: 0

    Hint: Look for pairs of numbers that add up to zero within the given range.

  3. Q3.easy

    A submarine is at 250 metres below sea level. It then ascends 75 metres and later descends 120 metres. What is its final position relative to sea level?
    1. A)195 m
    2. B)-195 m
    3. C)295 m
    4. D)-295 m
    Show answer

    Answer: -295 m

    Hint: Represent positions below sea level with negative integers and movements upwards with positive integers.

  4. Q4.medium

    Evaluate: ((-17) × 98) + ((-17) × 2) - ((-17) × 100).
    1. A)0
    2. B)-1700
    3. C)17
    4. D)-17
    Show answer

    Answer: 0

    Hint: Look for a common factor in all three terms and apply the distributive property of multiplication over addition/subtraction.

  5. Q5.medium

    A submarine starts at 250 meters below sea level. It then ascends 120 meters, and later descends 180 meters. If the sea level is represented by 0, what is the final depth of the submarine?
    1. A)-310 meters
    2. B)-290 meters
    3. C)-190 meters
    4. D)-350 meters
    Show answer

    Answer: -310 meters

    Hint: Represent 'below sea level' with negative integers and 'ascends' as addition, 'descends' as subtraction.

  6. Q6.medium

    How many integers 'x' satisfy the condition |x - 5| < 3?
    1. A)5
    2. B)6
    3. C)7
    4. D)8
    Show answer

    Answer: 5

    Hint: The condition |A| < B means -B < A < B. Convert the absolute value inequality into a compound inequality.

  7. Q7.hard

    If x is an integer, what is the smallest possible value of |x - 5| + |x + 3|?
    1. A)A) 0
    2. B)B) 2
    3. C)C) 8
    4. D)D) 10
    Show answer

    Answer: C) 8

    Hint: Think of |a - b| as the distance between 'a' and 'b' on the number line. The expression asks for the sum of distances from 'x' to 5 and from 'x' to -3.

  8. Q8.hard

    A sequence of integers is defined by a₁ = 1, and aₙ = aₙ₋₁ - (-1)ⁿ for n > 1. What is the value of a₁₀₀?
    1. A)A) -1
    2. B)B) 0
    3. C)C) 1
    4. D)D) 100
    Show answer

    Answer: B) 0

    Hint: Calculate the first few terms of the sequence to identify a repeating pattern or a trend.

  9. Q9.hard

    Calculate the value of 17 × (-23) + 17 × (-12) - 17 × 5 - 17 × (-10).
    1. A)A) -510
    2. B)B) -340
    3. C)C) 170
    4. D)D) 510
    Show answer

    Answer: A) -510

    Hint: Look for common factors in the terms and apply the distributive property to simplify the calculation.

These are 9 of the 59 questions available for Integers. Start practicing above to unlock visual solutions, AI coaching, and the topic leaderboard — completely free.