A shop displays a jacket for Rs 5,000. It offers successive discounts of 10% and then 20%. Which property explains why calculating 20% first, then 10%, yields the exact same final price?

Answer: Commutative Property of Multiplication. Final Price = 5000 × 0.90 × 0.80. Since order of multiplication does not matter (A × B = B × A), it is commutative.

You have 3 identical empty boxes. If you try to divide 12 apples equally among 0 boxes, what happens conceptually?

Answer: The task is physically impossible (Undefined). Division by zero implies distributing items into zero groups, which is a structural impossibility. Thus, 12 ÷ 0 is undefined.

A submarine is at -150 meters altitude (below sea level) and drops another 50 meters. A bird is flying at +200 meters. What is the absolute distance between them?

Answer: 400 meters. Submarine drops: -150 - 50 = -200m. Bird: +200m. Distance = |200 - (-200)| = |200 + 200| = 400m.

A teacher asks you to calculate 18 × 102 mentally. Which algebraic property makes it easier to calculate as 18 × (100 + 2)?

Answer: Distributive Property. Distributive property lets you distribute multiplication over addition: 18(100 + 2) = 1800 + 36 = 1836.

If an elevator goes up 5 floors (+5), down 8 floors (-8), and up 3 floors (+3), its net displacement is 0. This is a practical example of:

Answer: Additive Inverse. Upward movement (+8 total) is canceled exactly by downward movement (-8). (+8) + (-8) = 0 is additive inverse.

On a thermometer, yesterday's temp was -12°C. Today's is 4°C. The calculation 4 - (-12) represents:

Answer: The difference/rise in temperature. Subtracting a negative implies finding the gap or rise. 4 - (-12) = 16°C rise.

If multiplying your bank balance by 'X' leaves your balance exactly the same, what is X called?

Answer: Multiplicative Identity. The number 1 is the Multiplicative Identity because N × 1 = N.

You owe Rs 500 (balance is -500). If someone gives you half their debt (-250), your new balance equation is (-500) + (-250). Is this larger or smaller than before?

Answer: Smaller. New balance = -750. In negative numbers, a higher magnitude means a smaller value.

A square carpet covers an exact area of 144 sq meters. To find the side length, you use a process that reverses multiplication. This process is:

Answer: Square Root. Area = Side × Side (x²). To reverse x², you take the Square Root.

Two cars travel in exact OPPOSITE directions on a highway at 60 km/h and 40 km/h. By adding their speeds to calculate separation, you are using the concept of:

Answer: Relative Speed. When objects move in opposite directions, their relative arithmetic speed is the SUM of their individual speeds.

Calculate: -45 - (-20) + 15

Answer: -10. Two negatives make a positive: -45 + 20 + 15 = -45 + 35 = -10.

Find the value of | -8 + 3 | × | 2 - 5 |

Answer: 15. |-5| × |-3| = 5 × 3 = 15. Absolute value removes the negative sign entirely.

Solve using arithmetic properties: 25 × 87 × 4

Answer: 8700. Commutative property allows rearranging: (25 × 4) × 87 = 100 × 87 = 8700.

Find the product of the additive inverse and multiplicative inverse of 5.

Answer: -1. Additive inverse of 5 is -5. Multiplicative inverse of 5 is 1/5. Product = -5 × (1/5) = -1.

If x = -2 and y = 3, what is the value of x3 + y2?

Answer: 1. (-2)3 = -8 (Odd power keeps negative). (3)2 = 9. Sum = -8 + 9 = +1.

Answer: 70. Shift decimals 2 places: 840 ÷ 12. 12 × 7 = 84, so 12 × 70 = 840.

Which equation demonstrates the Associative Property of Multiplication?

Answer: (2 × 3) × 4 = 2 × (3 × 4). Associative means changing the grouping/brackets without changing the result.

Simplify: -[-(-(-5))] × 2

Answer: 10. Count the negatives: There are 4 negative signs. Even number of '-' yields positive. Result = +5. Then +5 × 2 = 10.

Answer: 25. Shift decimals: 1 / 0.04 = 100 / 4 = 25.

If N is an even number, what is the nature of (-1)N + (-1)N+1?

Answer: Always 0. If N is even (-1)^even = +1. Then N+1 is odd, (-1)^odd = -1. Sum = 1 + (-1) = 0.

Calculate the exact value of the square root of 0.0009.

Answer: 0.03. Square root halves the number of decimal places. 4 places become 2 places. √9 = 3. Answer: 0.03.

Of the numbers: 2, 0, -5, 1/2. Which has no multiplicative inverse?

Answer: 0. The multiplicative inverse of A is 1/A. For 0, 1/0 is undefined.

If A = 5, B = -2, find the value of (A - B) - (B - A)

Answer: 14. (A - B) = 5 - (-2) = 7. (B - A) = -2 - 5 = -7. Equation = 7 - (-7) = 14.

Simplify: |15 - 25| ÷ |20 - 15| + 5

Answer: 7. |-10| ÷ |5| + 5 → 10 ÷ 5 + 5. Division first: 2 + 5 = 7.

Find the cube root of -0.008.

Answer: -0.2. Cube root of negative is negative. Cube root of 8 is 2. Decimal places are divided by 3 (from 3 places to 1). Result: -0.2.

If x and y are negative integers, which of the following MUST be positive?

Answer: (x × y)3. Let x=-1, y=-2. x+y = -3 (Neg). x-y = 1 (Pos, but if x=-3, y=-1, then x-y=-2, so not always). x²y = 1*-2 = -2 (Neg). (xy)³ = (-1 * -2)³ = 2³ = 8 (Always Pos).

Simplify: 10.1 + 10.01 + 10.001

Answer: 1110. 1/0.1 = 10. 1/0.01 = 100. 1/0.001 = 1000. Sum = 10 + 100 + 1000 = 1110.

Let a # b = (a × b) + (a ÷ b). Find the value of 8 # 2.

Answer: 20. Plug in the values: (8 × 2) + (8 ÷ 2) = 16 + 4 = 20.

Find the value of | 2 - |3 - 7| | + | -5 |

Answer: 7. Inner bracket: |3-7| = |-4| = 4. Substitute back: |2 - 4| = |-2| = 2. Right bracket: |-5| = 5. Final Sum = 2 + 5 = 7.

Answer: 249. Half means divide by 2. Thus, 250 ÷ 21. Using indices rules: 2(50-1) = 249.

A shop displays a jacket for Rs 5,000. It offers successive discounts of 10% and then 20%. Which property explains why calculating 20% first, then 10%, yields the exact same final price?

Commutative Property of Multiplication

Associative Property of Addition

You have 3 identical empty boxes. If you try to divide 12 apples equally among 0 boxes, what happens conceptually?

The task is physically impossible (Undefined)

On a thermometer, yesterday's temp was -12°C. Today's is 4°C. The calculation 4 - (-12) represents:

The difference/rise in temperature

Home/Rajasthan Librarian Exam/Quantitative Aptitude/

Arithmetic Fundamentals

The absolute basics. Master addition, subtraction, multiplication, and division properties. Understand Absolute Values and Nested Operations.

Expert Answer & Key Takeaways

The absolute basics. Master addition, subtraction, multiplication, and division properties. Understand Absolute Values and Nested Operations.

1. Properties of Operations

Understanding how numbers interact mathematically.

Commutative: Order doesn't matter. (A + B = B + A) and (A × B = B × A). Does not work for Subtraction or Division!
Associative: Grouping doesn't matter. (A + B) + C = A + (B + C). Check this with multiplication too.
Distributive: Multiplication distributes over addition. A(B + C) = AB + AC.

Example:

Q: Which property justifies: 5 × (4 + 3) = (5 × 4) + (5 × 3)?

Solution: The Distributive Property.

2. Identity & Inverse Elements

Special numbers that revert operations.

Additive Identity: 0. (A + 0 = A)
Multiplicative Identity: 1. (A × 1 = A)
Additive Inverse: -A. (A + (-A) = 0)
Multiplicative Inverse: 1/A. (A × 1/A = 1)

Example:

Q: What is the additive inverse of -15?

Solution: The number that adds to -15 to make 0 is +15.

3. Absolute Value (Modulus)

The absolute value |X| measures distance from zero. It is NEVER negative.
If X < 0, then |X| = -X (which makes it positive).
If X ≥ 0, then |X| = X.

Example:

Q: What is the value of |-5| + |3|?

Solution: |-5| = 5. |3| = 3. Sum = 5 + 3 = 8.

4. Concept of Square and Cube Roots

Roots reverse powers. x asks 'what number squared equals x?'
Cubes preserve negative signs: (-2)³ = -8. Thus, cube root of -8 handles negatives normally (-2).

Example:

Q: Is the square root of -9 equal to -3?

Solution: No. (-3) × (-3) = +9. The square root of a negative number is not a real number.

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Arithmetic Fundamentals

Expert Answer & Key Takeaways

1. Properties of Operations

2. Identity & Inverse Elements

3. Absolute Value (Modulus)

4. Concept of Square and Cube Roots

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